Countercurrent protection device

Abstract

The invention provides a backflow protection device which comprises a backflow pipeline arranged between an artery and a vein, and the backflow pipeline comprises a main pipeline, a hemostasis valve and a filtering pipeline which are connected in sequence; the filtering pipeline comprises an inflow pipeline, a middle pipeline and an outflow pipeline which are sequentially connected, the inflow pipeline is connected to the hemostasis valve, and a filter is arranged on the middle pipeline; wherein the inner diameter and the length of the return pipeline are configured in a way that the total fluid resistance coefficient K of the return pipeline is greater than or equal to 2.0 ml <-1 > and less than or equal to 3.0 ml <-1 >. Through the configuration, the long-standing problem that the countercurrent flushing effect and cerebral perfusion cannot be balanced is solved.

Description

Technical Field

[0001] This invention relates to the field of medical device technology, and in particular to a reflux protection device used in percutaneous reflux brain protection carotid artery revascularization surgery. Background Technology

[0002] PCAR (Percutaneous Carotid Revascularization with Internal Carotid Artery) is a technique that creates an extracorporeal blood circulation system from artery to vein, allowing blood to flow in reverse. The arterial end of the device used in this technique is inserted into an artery such as the carotid artery, and the venous end is inserted into a vein such as the femoral vein. Due to the pressure difference between the arteries and veins, the arterial end of the device also has the same pressure difference as between the arteries and veins. In this way, by reversing blood flow in the internal carotid artery, plaque is filtered, and plaque treatment is achieved, thus protecting the brain. However, current PCAR techniques lack quantitative design and control of the fluid resistance of the extracorporeal return tubing, leading to unstable intraoperative backflow rates. This makes it difficult to achieve a reliable and optimal balance between effectively removing plaque and ensuring continuous brain perfusion, posing a risk of cerebral ischemia or residual plaque. Summary of the Invention

[0003] The purpose of this application is to provide a backflow protection device to solve the long-standing technical problem of the inability to balance the backflow flushing effect with brain perfusion.

[0004] To achieve the above objectives, this application provides a backflow protection device, comprising a reflux line disposed between an artery and a vein. The reflux line includes at least a main line, a hemostatic valve, and a filter line connected in sequence. The filter line includes an inflow line, an intermediate line, and an outflow line connected in sequence. The inflow line is connected to the hemostatic valve, and a filter is disposed on the intermediate line. The total fluid resistance coefficient K of the reflux line satisfies: 2.0 ml. -1 ≤K≤3.0 ml -1 .

[0005] In some embodiments, the fluid resistance coefficient of the filtration pipeline is adjustable and has a high resistance state and a low resistance state; in the high resistance state, the fluid resistance coefficient of the filtration pipeline is 1.12 ml. -1 ~1.52 ml -1 Under the low-resistance condition, the fluid resistance coefficient of the filter pipeline is 0.31 ml. -1 ~0.71 ml -1 .

[0006] In some embodiments, the reflux line further includes a three-way valve; at least one of the three-way valves is provided between the hemostatic valve and the inflow line; and / or, at least one of the three-way valves is provided on the outflow line.

[0007] In some embodiments, the intermediate pipeline is provided with a housing, and the filter is disposed inside the housing; the housing is provided with an adjustable resistance structure for adjusting the fluid resistance coefficient of the filter pipeline.

[0008] In some embodiments, the adjustable resistance structure is a button, which can switch between at least a first gear and a second gear; when the button is in the first gear, it can increase the fluid resistance coefficient of the filter pipeline, and when the button is in the second gear, it does not change the fluid resistance coefficient of the filter pipeline.

[0009] In some embodiments, the backflow rate in the return line is 18 ml / min to 70 ml / min.

[0010] In some embodiments, the reflux line further includes a catheter sheath connected to the outflow line for insertion into a vein.

[0011] In some embodiments, the backflow protection device further includes a dual-balloon occlusion catheter, wherein an opening is provided between the two balloons at its distal end; wherein the main tube is formed by the catheter body of the dual-balloon occlusion catheter extending from the opening to the proximal end; or, the main tube is formed by an intermediate catheter, which is disposed inside the dual-balloon occlusion catheter, and the distal end of the intermediate catheter passes through and extends out of the opening.

[0012] In some embodiments, the return line satisfies at least one of the following conditions:

[0013] The main pipeline has a length of 300mm~350mm and an inner diameter of 2.3mm~2.6mm;

[0014] The length of the internal flow-limiting cavity of the hemostatic valve is 20mm~40mm, and the inner diameter of the flow-limiting cavity is 1.6mm~1.9mm;

[0015] The length of the inflow pipe is 150mm~350mm, and the inner diameter is 4mm~5mm;

[0016] The length of the intermediate pipeline is 120mm~220mm, and the inner diameter is 2mm~3mm;

[0017] The length of the outflow pipe is 350mm~450mm, and the inner diameter is 4mm~5mm.

[0018] In some embodiments, the formula for calculating the total fluid resistance coefficient of the return pipeline is as follows:

[0019] ;

[0020] in: The number of structures in the return pipeline that require calculation of fluid resistance. ≥5; For the first The length of the structure whose fluid resistance needs to be calculated; For the first The inner diameter of a structure for which fluid resistance needs to be calculated.

[0021] As described above, this application provides a backflow protection device suitable for PCAR (percutaneous retrograde cerebral protection carotid revascularization). The backflow protection device includes a return tubing positioned between an artery and a vein. The return tubing includes at least a main tubing, a hemostatic valve, and a filter tubing connected in sequence. The filter tubing includes an inflow tubing, an intermediate tubing, and an outflow tubing connected in sequence. The inflow tubing is connected to the hemostatic valve, and a filter is installed on the intermediate tubing. The inner diameter and length of the return tubing are configured such that the total fluid resistance coefficient K of the return tubing satisfies 2.0 ml. -1 ≤K≤3.0 ml -1 This configuration can resolve the contradiction between excessive flow leading to cerebral ischemia and insufficient flow leading to poor plaque filtration in reflux cerebral protection by adjusting the fluid resistance coefficient of the entire reflux pipeline, ultimately achieving a balance between cerebral perfusion and reflux effect. Attached Figure Description

[0022] Those skilled in the art will understand that the accompanying drawings are provided to better understand the invention and do not constitute any limitation on the scope of the invention.

[0023] Figure 1 This is a schematic diagram of the basic structure of the backflow protection device according to an embodiment of this application;

[0024] Figure 2 for Figure 1 A schematic diagram of the location of each pipe in the return pipeline of the backflow protection device. In the diagram, L1, L2, L3, L4, and L5 are the lengths of the main pipeline, hemostatic valve, inflow pipeline, intermediate pipeline, and outflow pipeline, respectively.

[0025] Figure 3 for Figure 1 A cross-sectional diagram of the backflow protection device at positions A, B, C, D, and E in the pipeline. In the diagram, D1, D2, D3, D4, and D5 are the inner diameters of the main pipeline, hemostatic valve, inflow pipeline, intermediate pipeline, and outflow pipeline, respectively.

[0026] Figure 4 This is a schematic diagram of the implantation location of the double balloon occlusion catheter according to an embodiment of this application. The yellow highlighted part in the figure represents the plaque.

[0027] Figure 5The countercurrent flow rate test results provided in this application under different cerebral perfusion pressures and different fluid resistance coefficients are shown on the vertical axis, where the flow rate (ml / min) is represented by the vertical axis and the total fluid resistance coefficient (unit: ml) is represented by the horizontal axis. -1 );

[0028] Figure 6 This application provides an improved schematic diagram of the backflow protection device. In the diagram, two three-way valves are provided between the inflow pipe and the hemostatic valve, and a three-way valve is provided on the outflow pipe. The proximal end of the outflow pipe is connected to the catheter sheath.

[0029] Figure 7 for Figure 6 A cross-sectional diagram of the return pipeline of the backflow protection device at five pipeline positions: A, B, C, D, and F. Pipeline F is a three-way valve.

[0030] Figure 8 This is a schematic diagram of the filter structure according to an embodiment of this application;

[0031] Figure 9 The total fluid resistance coefficient of the reflux pipeline in this application is 2.33 ml. -1 Experimental results of countercurrent flow rate under different injection pressures, with the vertical axis representing flow rate (ml / min) and the horizontal axis representing injection pressure (unit, mmhg).

[0032] Figure 10 This application provides an improved structural schematic diagram of the backflow protection device according to an embodiment of the application. In the diagram, two three-way valves are provided between the inflow pipe and the hemostatic valve, and one three-way valve is provided on the outflow pipe.

[0033] Figure 11 for Figure 10 The diagram shows the cross-sectional views of the backflow protection device at five pipeline locations: A, B, C, D, and F. The F pipeline section is a three-way valve.

[0034] Explanation of reference numerals in the attached diagram: 1-External carotid artery, 2-Common carotid artery, 3-Internal carotid artery, 100-Double balloon occlusion catheter, 101-Distal balloon, 102-Proximal balloon, 103-Opening, 110-Main tube, 200-Filtering tube, 201-Shell, 202-Button, 210-Inflow tube, 220-Intermediate tube, 230-Outflow tube, 240-Filter, 300-Hemostatic valve, 400-Catheter sheath, 500-Three-way valve, 600-Intermediate catheter. Detailed Implementation

[0035] The following specific examples illustrate the implementation of this application. Those skilled in the art can easily understand other advantages and effects of this application from the content disclosed in this specification. This application can also be implemented or applied through other different specific embodiments, and various details in this specification can also be modified or changed based on different viewpoints and applications without departing from the spirit of this application. It should be noted that the illustrations provided in this embodiment are only schematic representations of the basic concept of this application. Therefore, the drawings only show components related to this application and are not drawn according to the actual number, shape, and size of components in the implementation. In actual implementation, the type, quantity, and proportion of each component can be arbitrarily changed, and the component layout may also be more complex.

[0036] Furthermore, while each embodiment described below possesses one or more technical features, this does not imply that users of this application must simultaneously implement all technical features in any embodiment, or can only separately implement some or all technical features in different embodiments. In other words, where implementation is possible, those skilled in the art can selectively implement some or all of the technical features in any embodiment, or selectively implement a combination of some or all of the technical features in multiple embodiments, based on the disclosure of this application and depending on design specifications or implementation requirements, thereby increasing the flexibility in implementing this application.

[0037] As used herein, the singular forms “a,” “an,” and “the” include plural objects, and the plural form “multiple” includes two or more objects, unless otherwise expressly indicated. As used herein, the term “or” is generally used to include the meaning of “and / or,” unless otherwise expressly indicated, and the terms “installed,” “connected,” and “linked” should be interpreted broadly, for example, as a fixed connection, a detachable connection, or an integral connection. Connections can be mechanical or electrical. Connections can be direct or indirect through an intermediate medium, and can be internal communication between two elements or an interaction between two elements. Relational terms such as “first,” “second,” etc., are used merely to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations, nor do they indicate or imply relative importance or implicitly specify the number of indicated technical features. It should be understood that the terms "center," "longitudinal," "lateral," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "axial," "radial," and "circumferential," etc., indicating orientation or positional relationships, are based on the orientation or positional relationships shown in the accompanying drawings and are used 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. Those skilled in the art can understand the specific meaning of the above terms in this application according to the specific circumstances.

[0038] The core of this application lies in providing a backflow protection device to resolve the contradiction in backflow cerebral protection between excessive flow leading to cerebral ischemia and insufficient flow leading to poor plaque filtration. This application resolves a long-standing technical contradiction by precisely designing the total fluid resistance coefficient of the backflow pipeline to balance cerebral perfusion and backflow effect. The following description refers to the accompanying drawings.

[0039] Figure 1 This is a schematic diagram of the basic structure of the backflow protection device according to an embodiment of this application. Figure 2 for Figure 1 A schematic diagram of the positions of each pipe in the return pipeline of the backflow protection device. In the diagram, L1, L2, L3, L4, and L5 are the lengths of the main pipeline 110, the hemostatic valve 300, the inflow pipeline 210, the intermediate pipeline 220, and the outflow pipeline 230, respectively. Figure 3 for Figure 1The diagram shows the cross-sectional views of the backflow protection device at positions A, B, C, D, and E in the pipelines. In the diagram, D1, D2, D3, D4, and D5 are the inner diameters of the main pipeline 110, the hemostatic valve 300, the inflow pipeline 210, the intermediate pipeline 220, and the outflow pipeline 230, respectively.

[0040] like Figures 1-3 As shown, the backflow protection device of this application embodiment includes a double-balloon occlusion catheter 100, a hemostatic valve 300, and a filter line 200 connected in sequence; that is, the proximal end of the double-balloon occlusion catheter 100 and the distal end of the filter line 200 are connected by the hemostatic valve 300. Thus, the double-balloon occlusion catheter 100, the hemostatic valve 300, and the filter line 200 together define a backflow path.

[0041] The dual-balloon occlusion catheter 100 is a key device for achieving reverse blood flow and surgical area isolation. It is placed in the carotid artery region to block forward blood flow and create a controlled blood flow channel from the brain to the outside of the body.

[0042] The dual-balloon occlusion catheter 100 includes a catheter body and two balloons disposed at the distal end of the catheter body. The two balloons are a distal balloon 101 and a proximal balloon 102. An opening 103 is provided on the catheter body between the distal balloon 101 and the proximal balloon 102.

[0043] Figure 4 This is a schematic diagram showing the implantation location of the dual-balloon occlusion catheter 100 according to an embodiment of this application. Figure 4 As shown, the distal balloon 101 occludes the external carotid artery (ECA) 1, and the proximal balloon 102 occludes the common carotid artery 2 (CCA). Thus, when the distal balloon 101 and the proximal balloon 102 are inflated, an isolated working chamber is formed between them. At this time, the blood supply to the posterior part of the brain relies on compensatory blood flow from the circle of Willis (circle of arteries at the base of the brain).

[0044] Because the proximal balloon 102 blocks the forward blood flow from the heart, and the pressure inside the brain is higher than in the isolated working chamber, blood naturally flows from the high-pressure area to the low-pressure area. Therefore, blood flows backward from the Willis ring via the internal carotid artery (ICA) 3 and into the double-balloon occlusion catheter 100 through the opening 103 at the distal end. Thus, during carotid plaque treatment (such as stent implantation or plaque resection), any dislodged debris will be carried away by this reverse blood flow. Figure 4 The arrows indicate the direction of the flow (upstream) and are carried out of the body instead of flowing downstream into the brain, thus playing a role in brain protection.

[0045] In addition, the filtration tubing 200 is responsible for filtering backflowing blood and safely returning it to the venous system. Specifically, the distal end of the filtration tubing 200 is connected to a hemostatic valve 300 to receive blood flowing back from the internal carotid artery 3. In some embodiments, the proximal end of the filtration tubing 200 can be inserted into the femoral vein via a catheter sheath 400 (such as a venous sheath or a venous sheath collateral) to return the filtered blood to the body, see [link to relevant documentation]. Figure 6 or Figure 10 As shown.

[0046] Therefore, the backflow protection device of this application is responsible for collecting and filtering backflowing blood through its reflux line and safely returning it to the venous system.

[0047] As is easily understood, the entire backflow protection device is driven by the automatic venous pressure differential (P1-P2). The pressure is higher at the backflow end of the internal carotid artery (arterial end) (generally 90-180 mmHg), and lower at the femoral vein (venous end) (generally 10-20 mmHg). This natural pressure differential drives blood to flow automatically from the arterial segment (pressure P1) between the two balloons of the double-balloon occlusion catheter 100 to the venous segment (pressure P2) proximal to the filter line 200.

[0048] Furthermore, according to the fluid mechanics formula:

[0049] (1)

[0050] It can be seen that, under a fixed arteriovenous pressure differential ( Under ) traffic ( The total resistance determines the blood flow rate. Furthermore, blood flow and cerebral perfusion pressure (CPF) are also affected. The flow rate is directly proportional to the blood pressure; the higher the blood pressure, the greater the flow rate. The larger the value, the greater the resistance. Where: R represents fluid resistance; r represents pipe radius; L represents pipe length; This indicates that fluid resistance is related to the pipe radius and pipe length.

[0051] Based on fluid mechanics theory, the Hagen-Poiseuille law states that for the flow of an incompressible Newtonian fluid in a uniform rigid circular straight pipe under laminar flow conditions, the formula for calculating the fluid resistance R is:

[0052] (2)

[0053] Where η represents the kinetic viscosity of blood. In actual calculations, blood viscosity can be treated as a constant.

[0054] Combining formulas (1) and (2), it can be seen that the perfusion pressure and flow rate are related to blood viscosity, tube length and tube inner diameter.

[0055] Therefore, the core of this application lies in the precise design of the total fluid resistance coefficient K of the reflux tubing to achieve optimal flow rate and avoid problems of excessive or insufficient flow. Thus, the core of this application is not the dual-balloon occlusion catheter 100, the hemostatic valve 300, or the filter tubing 200 themselves, but rather in treating the reflux tubing they collectively define as a system and setting an optimal range for its overall resistance coefficient to balance cerebral perfusion and reflux effects.

[0056] Specifically, the reflux pipeline described in this application includes a main pipeline 110, a hemostatic valve 300, and a filter pipeline 200 connected in sequence; wherein, the filter pipeline 200 includes an inflow pipeline 210, an intermediate pipeline 220, and an outflow pipeline 230 connected in sequence, the inflow pipeline 210 being directly or indirectly connected to the hemostatic valve 300, and a filter 240 being provided on the intermediate pipeline 220. Figure 1 As shown, the main inlet pipe 110 is located near the arterial segment (pressure P1), and the outlet pipe 230 is located near the venous segment (pressure P2). In some embodiments, the inlet pipe 210, the intermediate pipe 220, and the outlet pipe 230 are designed as a single unit, and their inner diameters may be the same or different.

[0057] In some embodiments, the main access route 110 is directly formed by the catheter body of the double balloon occlusion catheter 100 extending from the opening 103 to the proximal end of the double balloon occlusion catheter 100, with an axial length of L1. (See also...) Figures 1-2 and Figure 6 As shown.

[0058] In other embodiments, the main tubing 110 is directly composed of an intermediate conduit 600, which is disposed inside the double balloon occlusion conduit 100, with the distal end of the intermediate conduit 600 passing through and extending out of the opening 103. See details for further information. Figure 10 and Figure 11 As shown. At this time, the axial length of the main pipeline 110 is the total length of the intermediate conduit 600.

[0059] The hemostatic valve 300 is not limited to a Y-type. The inflow line 210 delivers blood from the hemostatic valve 300 into the intermediate line 220, where it is filtered by the filter 240 before flowing into the outflow line 230. The entire filtration line 200 serves as an extension tube, with its distal end easily connected to the double-balloon occlusion catheter 100. In some embodiments, the proximal end of the filtration line 200 is connected to the catheter sheath 400.

[0060] It should be understood that the reflux pipeline described in this application is not a simple pipe. It consists of multiple pipes, and each pipe (unless it has little impact on the flow rate and can be ignored) will generate a certain fluid resistance to blood flow. The sum of the resistance of all pipes is the total resistance of the system.

[0061] Further research revealed that when the resistance of the reflux tubing is too high, the backflow rate is too low, the backflow force is insufficient, and it is impossible to effectively remove plaque debris. Moreover, a "dead space" is easily formed within the device, which may lead to plaque debris residue and poor filtration effect. Conversely, when the resistance of the reflux tubing is too low, the backflow rate is too high, which will excessively divert the compensatory blood flow that should be supplied to the brain's Circle of Willis, leading to a "steal" phenomenon and causing cerebral ischemia.

[0062] Based on this, this application, through theoretical research and analysis of extensive experimental data, configures the inner diameter and length of the return pipe to such that the total fluid resistance coefficient K of the return pipe satisfies: 2.0 ml -1 ≤K≤3.0 ml -1 This range includes the endpoint value of 2.0 ml. -1 and 3.0 ml -1 And any value between the two endpoints, such as 2.1, 2.2, 2.3, 2.4, 2.5, 2.6, 2.7, 2.8, 2.9 ml. -1 wait.

[0063] Figure 5 The test results of the countercurrent flow rate provided in this application under different cerebral perfusion pressures and different fluid resistance coefficients are as follows. Figure 5 As shown, when the total fluid resistance coefficient of the return pipeline is <3.0 ml -1 It showed good backflow effect at different cerebral perfusion pressures, with flow rates greater than 18 ml / min. The total fluid resistance coefficient of the backflow was <2.0 ml. -1 The maximum flow rate can reach 70 ml / min, which is far greater than the actual demand and may lead to "blood theft".

[0064] Therefore, when the total fluid resistance coefficient K of the return pipeline is greater than 3.0 ml... -1 At this time, the resistance is too high and the flow rate is too low; when the total fluid resistance coefficient K < 2.0 ml -1 At this point, the resistance is too small and the flow rate is too large. Therefore, the optimal range for the total fluid resistance coefficient K is 2.0 ml. -1 ~3.0 ml -1 Within this range, a stable and sufficient backflow rate (e.g., 18-70 ml / min) can be generated, which can effectively filter plaques without excessively affecting cerebral perfusion, thus achieving the goal of both filtering plaques and ensuring normal cerebral blood supply.

[0065] In some embodiments, the fluid resistance coefficient of the filter pipe 200 can be adjusted by relevant means, so that even with a fixed inner diameter and length, the fluid resistance can be adjusted through additional structures, thereby improving flexibility.

[0066] In some embodiments, the filter pipeline 200 has a high-resistance state and a low-resistance state, wherein the fluid resistance coefficient in the high-resistance state is greater than the fluid resistance coefficient in the low-resistance state.

[0067] In some embodiments, under the high-resistance condition, the fluid resistance coefficient of the filter line 200 is 1.12 ml. -1 ~1.52 ml -1 .

[0068] In some embodiments, under the low-resistance condition, the fluid resistance coefficient of the filter line 200 is 0.31 ml. -1 ~0.71 ml -1 .

[0069] like Figure 8 As shown, in some embodiments, the intermediate pipeline 220 is provided with a housing 201, and the filter 240 is disposed inside the housing 201; and the housing 201 is provided with an adjustable resistance structure for adjusting the fluid resistance coefficient of the filter pipeline 200, so that the fluid resistance coefficient of the filter pipeline 200 can be increased or decreased.

[0070] Furthermore, the adjustable resistance structure is a button 202, which can directly control the deformation of the intermediate pipeline 220 by pressing the button 202.

[0071] In some embodiments, the button 202 is at least switchable between a first setting (i.e., a low flow rate setting) and a second setting (a high flow rate setting). In the first setting, the button 202 increases the fluid resistance coefficient of the filter pipe 200, while in the second setting, it does not change the fluid resistance coefficient of the filter pipe 200. Specifically, the button 202 can apply force to the intermediate pipe 220, causing it to deform and decrease or increase its inner diameter. For example, in the second setting, the button 202 is not triggered, keeping the inner diameter of the intermediate pipe 220 unchanged, thus not changing the fluid resistance coefficient of the filter pipe 200.

[0072] Of course, in some other embodiments, the button 202 can be replaced by other suitable means to achieve essentially the same function, which makes the fluid resistance of the filter line 200 itself flexibly adjustable.

[0073] In some embodiments, a check valve (not shown) is provided on one side of the intermediate pipeline 220 near the filter 240 to prevent backflow. The fluid resistance of the check valve should also be considered when calculating the total fluid resistance coefficient of the backflow pipeline.

[0074] In some embodiments, for the purpose of unifying dimensions and simplifying calculations, the total fluid resistance coefficient of the return pipe is based on formula (2) and calculated using the following formula (3):

[0075] (3)

[0076] in: In this embodiment of the system, to account for the number of structures in the return pipeline that require calculation of fluid resistance, ≥5; For the first The length of the structure whose fluid resistance needs to be calculated; For the first The inner diameter (i.e., diameter) of a structure for which fluid resistance needs to be calculated.

[0077] Structures requiring fluid resistance calculation include: main pipe 110, hemostatic valve 300, and filter pipe 300. In addition, if valves such as three-way valves or check valves are present, their resistance must also be calculated. Furthermore, any structures with adjustable resistance must also be calculated. In short, all structures that affect fluid resistance need to be calculated to ensure that the total fluid resistance coefficient K of the return pipe meets the requirement of 2.0 ml. -1 ≤K≤3.0 ml -1 .

[0078] The inner diameter and dimensions of the main pipe 110, hemostatic valve 300, and filter pipe 300 can be adjusted according to the backflow rate. An illustrative explanation follows.

[0079] In some embodiments, the length L1 of the main pipeline 110 is 300mm~350mm, and the inner diameter D1 is 2.3mm~2.6mm.

[0080] In some embodiments, the length L2 of the internal flow-limiting cavity of the hemostatic valve 300 is 20mm~40mm, and the inner diameter D2 of the flow-limiting cavity is 1.6mm~1.9mm.

[0081] In some embodiments, the length L3 of the inflow pipe 210 is 150mm~350mm, and the inner diameter D3 is 4mm~5mm.

[0082] In some embodiments, the length L4 of the intermediate pipe 220 is 120mm~220mm, and the inner diameter D4 is 2mm~3mm.

[0083] In some embodiments, the length L5 of the outflow pipe 230 is 350mm~450mm, and the inner diameter D5 is 4mm~5mm.

[0084] therefore, Figures 1 to 3The described backflow protection device is a basic structure, with the hemostatic valve 300 directly connected to the inflow line 210, and no valve (such as a three-way valve for infusion) installed on the outflow line 230. Based on this, a valve, typically a three-way valve 500, can be added to the filter line 200. The three-way valve 500 can be used for infusion, etc.

[0085] In some embodiments, at least one three-way valve 500 is provided between the hemostatic valve 300 and the inflow line 210.

[0086] In some embodiments, at least one three-way valve 500 is provided on the outflow pipe 230.

[0087] In a specific example, such as Figure 6 and Figure 10 As shown, two three-way valves 500 are installed between the hemostatic valve 300 and the inflow pipe 210, and the two three-way valves 500 are connected in series. At the same time, a three-way valve 500 is installed on the outflow pipe 230.

[0088] Of course, only one three-way valve 500 can be installed between the hemostatic valve 300 and the inflow pipe 210, or three or more three-way valves 500 can be installed. Similarly, only one three-way valve 500 can be installed on the outflow pipe 230, or two, three or more three-way valves 500 can be installed.

[0089] Therefore, when calculating the total fluid resistance coefficient of the return line, the fluid resistance of all three-way valves 500 must also be considered. In addition, when the proximal end of the filter line 200 is connected to the catheter sheath 400, the fluid resistance of the catheter sheath 400 should also be considered.

[0090] As easily understood, the three-way valve 500, which switches the flow direction, has a smaller valve core orifice, significantly impacting flow rate and generating substantial fluid resistance to blood flow. It is a high-resistance element and a major contributor to the overall system resistance. In contrast, the valve used for hemostasis, with its side branches lacking a valve core, has a weaker impact on flow rate and is a low-resistance element. Therefore, with fixed pipeline dimensions, the total fluid resistance coefficient can be adjusted using the three-way valve 500, making the total fluid resistance coefficient of the return pipeline adjustable.

[0091] The type and number of valves used in the backflow protection device of this application are not limited, but at least one hemostatic valve 300, including but not limited to a Y-type hemostatic valve, must be provided at the proximal end of the double balloon occlusion catheter 100. Taking the Y-type hemostatic valve as an example, one port can be connected to a guidewire or other instruments (such as an intermediate catheter 600), which will be sealed during the operation without considering resistance. The other port of the Y-type hemostatic valve is directly connected to the filter tubing 200 or connected through a three-way valve 500.

[0092] The backflow protection device described in this application will be further explained below with specific examples.

[0093] like Figures 6-8 As shown, in a specific example, the main tubing 110 is composed of the catheter body of a double-balloon occlusion catheter 100, and a one-way valve is provided on one side of the filter 240. One one-way valve and one hemostatic valve 300 are respectively provided. Two three-way valves 500 are provided between the hemostatic valve 300 and the inflow tubing 210. Simultaneously, one three-way valve 500 is provided on the outflow tubing 230, and the proximal end of the outflow tubing 230 is connected to the catheter sheath 400, which is a venous sheath or collateral branch. For this structure, the inner diameter and length of the return tubing are shown in Table 1.

[0094] Table 1: Inner diameter and length configuration of return piping and corresponding fluid resistance coefficients

[0095]

[0096] In Table 1, the total fluid resistance coefficient of the return pipeline is 2.33 ml. -1 .

[0097] Figure 9 The total fluid resistance coefficient of the reflux pipeline in this application is 2.33 ml. -1 Experimental results of countercurrent flow rates under different injection pressures. From Figure 9 It can be seen that when the total fluid resistance coefficient of the return pipeline is 2.33 ml -1 At that time, the countercurrent flow rate was within the optimal range of 18 ml / min to 70 ml / min under different infusion pressures, which met the requirements.

[0098] Furthermore, in some embodiments, the fluid resistance coefficient of the filter line 200 is adjusted by switching between high and low flow rates to meet the needs of different application scenarios. As shown in Table 2, when button 202 is pressed to the first position, the fluid resistance coefficient of the filter line 200 can be increased, for example, by 0.81 ml. -1 When button 202 returns to the second position, the fluid resistance coefficient of filter tubing 200 remains unchanged. That is, before adjustment, the total fluid resistance coefficient of filter tubing 200 is 0.51 ml. -1 After adjustment, the total fluid resistance coefficient of filter tubing 200 is 1.33 ml. -1 .

[0099] Table 2: Filter pipe inner diameter and length configuration and corresponding fluid resistance coefficient

[0100]

[0101] like Figure 10 and Figure 11 As shown, in another specific example, an intermediate catheter 600 is added to the double balloon occlusion catheter 100 to complete the backflow of the entire procedure. Figure 11 Compared to the lumen A of the intermediate conduit 600 in the middle conduit Figure 3 The lumen A of the double-balloon occlusion catheter 100 is slightly reduced. At this time, button 202 can be switched to a higher position (such as the second position) to reduce the resistance coefficient, so that the total fluid resistance coefficient of the reflux line can be maintained at a resistance of 2.0 ml. -1 ~3.0ml -1 .

[0102] In summary, this application provides a reflux protection device suitable for percutaneous reflux brain-protective carotid artery revascularization. The reflux protection device includes a return tubing positioned between an artery and a vein. This return tubing includes at least a main tubing 110, a hemostatic valve 300, and a filter tubing 200 connected in sequence. The filter tubing 200 includes an inflow tubing 210, an intermediate tubing 220, and an outflow tubing 230 connected in sequence. The inflow tubing 210 is connected to the hemostatic valve 300, and a filter 240 is provided on the intermediate tubing 220. The inner diameter and length of the return tubing are configured such that the total fluid resistance coefficient K of the return tubing satisfies 2.0 ml. -1 ≤K≤3.0 ml -1 This configuration can resolve the contradiction between excessive flow leading to cerebral ischemia and insufficient flow leading to poor plaque filtration in reflux cerebral protection by adjusting the fluid resistance coefficient of the entire reflux pipeline, ultimately achieving a balance between cerebral perfusion and reflux effect.

[0103] It should be noted that the above embodiments can be combined with each other. The above description is only a description of preferred embodiments of the present invention and is not intended to limit the scope of the present invention in any way. Any changes or modifications made by those skilled in the art based on the above disclosure shall fall within the protection scope of the present invention.

Claims

1. A reverse flow protection device, characterized in that, The application relates to a blood return line for setting between an artery and a vein, comprising a main line, a hemostatic valve and a filter line connected in sequence; the filter line comprises an inflow line, an intermediate line and an outflow line connected in sequence, the inflow line is connected to the hemostatic valve, and a filter is arranged on the intermediate line; wherein: the inner diameter and length of the blood return line are configured so that the total fluid resistance coefficient K of the blood return line satisfies: 2.0 ml -1 <= K <= 3.0 ml -1 .

2. The reverse flow protection device of claim 1, wherein, The fluid resistance coefficient of the filter pipeline is adjustable and has a high resistance state and a low resistance state; in the high resistance state, the fluid resistance coefficient of the filter pipeline is 1.12 ml -1 ~1.52 ml -1 ; in the low resistance state, the fluid resistance coefficient of the filter pipeline is 0.31 ml -1 ~0.71 ml -1 .

3. The reverse flow protection device of claim 1, wherein, The reflux pipeline further comprises a three-way valve; at least one three-way valve is arranged between the hemostasis valve and the inflow pipeline; and / or, at least one three-way valve is arranged on the outflow pipeline.

4. The reverse flow protection device of claim 1, wherein, An outer shell is arranged outside the intermediate pipeline, and the filter is arranged in the outer shell; an adjustable resistance structure is arranged on the outer shell, and is used for adjusting the fluid resistance coefficient of the filter pipeline.

5. The reverse flow protection device of claim 4, wherein, The adjustable resistance structure is a button, and the button can be switched between at least a first gear and a second gear; the button can increase the fluid resistance coefficient of the filter pipeline when the button is in the first gear, and the fluid resistance coefficient of the filter pipeline is not changed when the button is in the second gear.

6. The reverse current protection device of claim 1, wherein The reverse flow rate in the reflux pipeline is 18ml / min~70ml / min.

7. The reverse current protection device of claim 1, wherein The reflux pipeline further comprises a catheter sheath connected to the outflow pipeline, and the catheter sheath is used for inserting into a vein.

8. The reverse current protection device of claim 1, wherein Further comprising a double-balloon occlusion catheter, and an opening is arranged between two balloons at the distal end of the double-balloon occlusion catheter; wherein the main pipeline is composed of a catheter body extending from the opening to the proximal end of the double-balloon occlusion catheter; or the main pipeline is composed of an intermediate catheter, and the intermediate catheter is arranged inside the double-balloon occlusion catheter, and the distal end of the intermediate catheter passes through and extends out of the opening.

9. The reverse current protection device of claim 1, wherein The reflux pipeline satisfies at least one of the following conditions: The length of the main pipeline is 300mm~350mm, and the inner diameter is 2.3mm~2.6mm; The length of the hemostasis valve is 20mm~40mm, and the inner diameter of the flow-limiting cavity is 1.6mm~1.9mm; The length of the inflow pipeline is 150mm~350mm, and the inner diameter is 4mm~5mm; The length of the intermediate pipeline is 120mm~220mm, and the inner diameter is 2mm~3mm; The length of the outflow pipeline is 350mm~450mm, and the inner diameter is 4mm~5mm.

10. The reverse current protection device of claim 1, wherein, The total fluid resistance coefficient of the reflux pipeline is calculated according to the following formula: ； wherein: is the number of structures for which fluid resistance needs to be calculated in the return line, ≥ 5; is the length of the th structure for which fluid resistance needs to be calculated; is the inner diameter of the th structure for which fluid resistance needs to be calculated.

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