An arteriovenous fistula system

Abstract

The application discloses an arteriovenous fistula system, and relates to the technical field of medical devices, which comprises a fistula catheter, a handle, a power transmission line and a power output controller. The application makes the operation of the fistula catheter head more convenient, realizes accurate detection of the relative displacement amount of the head electrode, makes the fistula catheter head not loosen even if the external force disappears after being closed, improves the structure of the heating electrode, and makes the size and angle of the fistula not adversely affect the blood flow. The application adds blood flow, blood pressure, temperature and other sensors in the fistula catheter, cooperates with the control function of the power output controller, realizes accurate detection of the opening and closing state of the fistula catheter head, automatic detection of the arteriovenous vessel wall capture, safe output of energy and heating control of the fistula catheter head electrode. The application is more beneficial to the operation of doctors in clinical use and can obtain better fistula effect.

Description

Technical Field

[0001] This invention relates to the field of medical device technology, and in particular to an arteriovenous fistula system. Background Technology

[0002] An endovenous arteriovenous fistula catheter, also known as an arteriovenous fistula tube, is a sterile, disposable medical device used in clinical arteriovenous fistula surgery. Its purpose is to create an arteriovenous fistula within the ventricle, establishing blood flow. Arteriovenous fistula surgery can reduce vascular trauma, decrease bleeding, reduce stimulation of intimal hyperplasia, and lower postoperative morbidity.

[0003] An arteriovenous fistula catheter, operating handle, and power output device constitute an arteriovenous fistula system; however, existing arteriovenous fistula systems have at least the following major drawbacks:

[0004] (1) The opening and closing structure of the fistula catheter tip is complex, and the opening and closing operation of the handle is very inconvenient; it is impossible to accurately detect whether the opening and closing structure of the fistula catheter tip is completely closed. If it is not completely closed, it cannot effectively form an intravascular fistula; after the fistula catheter tip is closed, it is easy to loosen naturally if the external force is removed, and it cannot effectively form an intravascular fistula.

[0005] (2) The heating electrode at the tip of the fistula catheter has structural design defects, and the size and angle of the generated arteriovenous fistula anastomosis can easily have an adverse effect on blood flow.

[0006] (3) The energy output device lacks core control functions and cannot automatically realize the accurate detection of the opening and closing status of the fistula catheter head, the automatic detection of arterial and venous vessel wall capture, the safe output of energy, and the heating control of the fistula catheter tip electrode. Doctors often need to rely on their own experience to perform auxiliary operations and judgments.

[0007] Due to the aforementioned shortcomings, the clinical effectiveness of existing arteriovenous fistula systems is poor. Doctors often cause medical accidents due to various operational problems, increasing the probability of surgical failure and thus limiting the use and popularization of arteriovenous fistula surgery in clinical practice. Summary of the Invention

[0008] In view of the above-mentioned defects or deficiencies in the prior art, the present invention provides an arteriovenous fistula system in order to solve all or part of the above-mentioned technical problems.

[0009] In one aspect, the present invention provides an arteriovenous fistula system, comprising: a fistula catheter, a handle, a power transmission line, and a power output controller;

[0010] The stoma catheter includes a first tube and a second tube. One end of the first tube is located inside the handle housing, and the other end is located outside the handle housing and connected to a base. The base has a first inclined surface, and a proximal electrode is installed on the first inclined surface. The second tube passes through the first tube, and its distal end is located outside the first tube and connected to a head end. The head end has a second inclined surface facing the first inclined surface, and a distal electrode is installed on the second inclined surface.

[0011] The handle includes a housing, a sliding assembly, an elastic pressure assembly, and a stroke detection assembly. A sliding button is mounted on the side wall of the housing. The sliding assembly is slidably installed within the housing and configured to slide between an open position and a closed position under the action of the sliding button. The elastic pressure assembly is connected to both the inner wall of the housing and the sliding assembly and is configured to apply a preload force to the sliding assembly in the direction from the open position to the closed position. The stroke detection assembly is connected to the sliding assembly and is configured to detect the sliding stroke of the sliding assembly.

[0012] The first tube or the second tube is connected to the sliding assembly. The sliding assembly slides from the open position to the closed position, driving the spaced proximal electrode and the distal electrode to a contact state.

[0013] One end of the power transmission line is connected to the power output controller, and the other end is electrically connected to the first tube or the second tube inside the handle housing;

[0014] The power output controller is used to detect blood flow rate or blood pressure based on sensors installed on the first and second tubes to determine whether the stent catheter has successfully captured the arterial and venous vessel walls; to calculate the distance between the proximal electrode and the distal electrode based on the measurement value of the sliding component by the stroke detection component; and to determine whether to activate energy output to heat the proximal electrode and / or the distal electrode based on the detection value of the temperature sensor installed on the first or second tube.

[0015] Furthermore, the stroke detection component includes a detection circuit, which includes a DC voltage source, a switch, a fixed resistor, and a sliding rheostat connected in series, with the two ends of the sliding rheostat connected in parallel with a voltmeter;

[0016] The sliding rheostat includes multiple conductive strips and a spring pin. The multiple conductive strips are evenly spaced in a preset direction in the detection area. Each conductive strip has the same resistance and is connected in series with each other. One end of the spring pin is installed on the sliding assembly and slides with the sliding assembly, and the other end is provided with a pointed tip that abuts against the conductive strip.

[0017] The power output controller is used to calculate the sequential number of the conductive strip currently pointed to by the tip of the spring needle based on the detected voltage value of the voltmeter, the resistance value of each conductive strip, the total number of conductive strips, the fixed resistance value, and the electromotive force of the DC voltage source; to calculate the actual travel distance of the spring needle based on the sequential number of the conductive strip currently pointed to by the tip of the spring needle and the interval distance between the conductive strips; and to determine the distance between the distal electrode and the proximal electrode based on the proportional relationship between the actual travel distance of the spring needle, the movable range of the spring needle, and the distance between the two electrode plates.

[0018] Furthermore, the power output controller calculates the sequential numbering of the conductive strips contacted by the tip of the spring pin according to the following formula:

[0019] φ n =φ×((Nn)×R) / (R0+(Nn)×R)

[0020] Where, φ n The voltage value detected by the voltmeter is represented by φ, the electromotive force of the DC voltage source is represented by R, the resistance value of each conductive strip is represented by R0, and n is the sequential number of the conductive strip that the tip of the spring needle contacts.

[0021] Furthermore, the proximal electrode plate is the heating end, and the distal electrode plate is the heated end;

[0022] Both the distal and proximal electrode pads are elliptical in shape. Each electrode pad includes an elliptical stoma area and an elliptical annular welding area. Both electrode pads form a 22° angle with the axis of the stoma catheter, and the maximum vertical distance between the end faces of the two electrode pads is 3 mm.

[0023] Furthermore, the major axis of the stoma region is 4.3 ± 0.5 mm, the minor axis is 1.6 mm ± 0.5 mm, and the area of ​​the stoma region is 3.3-7.9 mm². 2 The major axis of the outer ellipse of the welding area is 5.06±0.5mm, and the minor axis is 1.8±0.5mm. The inner ellipse of the welding area is the stoma region, and the maximum welding area of ​​the welding area does not exceed 6.7mm². 2 .

[0024] Furthermore, the base is provided with a heating element corresponding to the welding area. The heating element is an elliptical ring structure that is repeatedly bent. The two leads of the heating element are electrically connected to the power transmission line through the inside of the first tube.

[0025] Furthermore, the heating element is made of a high resistivity metal with a thickness of 0.05-0.2 mm.

[0026] Furthermore, a thermocouple for detecting the temperature of the heating element is provided inside the base.

[0027] The power output controller is used to control the temperature of the heating element to maintain at the target temperature value based on the temperature detection value of the thermocouple.

[0028] Furthermore, the target temperature value is 370±30℃.

[0029] Furthermore, the sliding assembly includes a slider and an elastic positioning element; the slider is connected to the elastic pressing assembly and the stroke detection assembly respectively, the first tube or the second tube is connected to the slider, and the outer wall of the slider is provided with a first positioning part and a second positioning part;

[0030] The elastic positioning member is installed on the inner wall of the handle housing and is configured to be able to position and cooperate with the first positioning part and the second positioning part.

[0031] The elastic pressure assembly includes a mounting base and an elastic element. The mounting base is fixedly connected to the inner wall of the handle. One end of the elastic element is connected to the mounting base, and the other end is connected to the sliding assembly. When the sliding assembly is between the open position and the closed position, the elastic element is compressed and has an elastic force in the direction from the open position to the closed position.

[0032] The arteriovenous fistula system provided by this invention has the following beneficial effects:

[0033] (1) The opening and closing structure of the fistula catheter tip has been improved and the internal operating structure of the handle has been redesigned, making the operation of the fistula catheter tip more convenient. By adding a stroke detection module to the handle, the relative displacement of the head electrode can be accurately detected, thereby accurately determining whether the opening and closing structure of the fistula catheter tip is completely closed.

[0034] (2) By setting a pre-tightening structure in the handle, the clamping electrode will not loosen even if the external force disappears after the tip of the fistula catheter is closed, thus ensuring the effective formation of an endovascular fistula.

[0035] (3) The structure of the heating electrode at the tip of the fistula catheter has been improved so that the size and angle of the generated arteriovenous fistula anastomosis will not have an adverse effect on blood flow.

[0036] (4) Sensors such as blood flow, blood pressure, and temperature have been added to the stoma catheter. Combined with the core control function of the power output controller, it can automatically realize the accurate detection of the opening and closing status of the stoma catheter head, the automatic detection of arterial and venous vessel wall capture, the safe output of energy, and the heating control of the stoma catheter tip electrode.

[0037] In summary, this invention overcomes the shortcomings of the prior art, is easier for doctors to operate in clinical use, and can achieve better fistula formation results. Attached Figure Description

[0038] Other features, objects, and advantages of this application will become more apparent from the following detailed description of non-limiting embodiments with reference to the accompanying drawings:

[0039] Figure 1 This is an overall layout diagram of an arteriovenous fistula system provided in one embodiment of this application;

[0040] Figure 2 This is a control circuit diagram of a power output controller provided in one embodiment of this application;

[0041] Figure 3 This is an operation flowchart of a power output controller provided in one embodiment of this application;

[0042] Figure 4 This is a schematic diagram of a PID control principle provided in one embodiment of this application;

[0043] Figure 5 This is a schematic diagram of a PID temperature control curve provided in one embodiment of this application;

[0044] Figure 6 This is a planar schematic diagram of the head electrode of a fistula catheter provided in one embodiment of this application;

[0045] Figure 7 This is a diagram showing the design parameters of the two-electrode area according to one embodiment of this application;

[0046] Figure 8 This is a schematic diagram of the tissue thickness and displacement between the two electrode pads before and after arteriovenous fistula formation according to one embodiment of this application;

[0047] Figure 9 This is an overall view of the handle provided in one embodiment of this application;

[0048] Figure 10 This is a schematic diagram of a travel detection structure provided in one embodiment of this application;

[0049] Figure 11 This is a schematic diagram of a travel detection circuit provided in one embodiment of this application;

[0050] Figure 12 This is a schematic diagram of a travel detection circuit provided in one embodiment of this application;

[0051] Figure 13 This is a front cross-sectional view of a handle provided in one embodiment of this application;

[0052] Figure 14This is a cross-sectional side view of the handle provided in one embodiment of this application;

[0053] Figure 15 This is a schematic diagram of the fistula catheter head provided in one embodiment of this application. Figure 1 ;

[0054] Figure 16 This is a schematic diagram of the fistula catheter head provided in one embodiment of this application. Figure 2 ;

[0055] Figure 17 This is a schematic diagram of the fistula catheter head provided in one embodiment of this application. Figure 3 . Detailed Implementation

[0056] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0057] The terminology used in the embodiments of this invention is for the purpose of describing particular embodiments only and is not intended to limit the invention. The singular forms “a,” “the,” and “the” as used in the embodiments of this invention and the appended claims are also intended to include the plural forms unless the context clearly indicates otherwise.

[0058] It should be understood that although the terms first, second, third, etc., may be used to describe the acquisition modules in the embodiments of the present invention, these acquisition modules should not be limited to these terms. These terms are only used to distinguish the acquisition modules from each other.

[0059] Depending on the context, the word "if" as used here can be interpreted as "when," "when," "in response to determination," or "in response to detection." Similarly, depending on the context, the phrase "if determination" or "if detection (of the stated condition or event)" can be interpreted as "when determination," "in response to determination," "when detection (of the stated condition or event)," or "in response to detection (of the stated condition or event)."

[0060] It should be noted that the directional terms such as "upper," "lower," "left," and "right" used in the embodiments of the present invention are used to describe the angles shown in the accompanying drawings and should not be construed as limiting the embodiments of the present invention. Furthermore, in the context, it should be understood that when it is mentioned that an element is formed "upper" or "lower" of another element, it can not only be formed directly "upper" or "lower" of the other element, but also indirectly "upper" or "lower" of the other element through an intermediate element.

[0061] To address the technical problems existing in the prior art, this embodiment provides an improved arteriovenous fistula system.

[0062] Figure 1 This is an overall layout diagram of the arteriovenous fistula system provided in this embodiment. The system includes a fistula catheter 1, a handle 2, a power transmission line 3, and a power output controller 4. The power control generator 4 applies thermal energy to the head electrode of the fistula catheter 1 through the power transmission line 3, thereby releasing thermal energy to the arteriovenous vessel wall, causing it to damage the tissue and create an arteriovenous fistula.

[0063] Figure 2 This is a schematic diagram of the control circuit for the power output controller 4. The industrial control motherboard is used for human-machine interaction. The MCU main control module is used for global control and monitoring of the underlying logic. The MCU core module is used for PID adjustment and feedback detection of the output capability. In case of an emergency, the MCU main control module can directly reset the MCU core module to prevent it from being in an uncontrolled state. Functional interaction is achieved through peripheral modules of the control circuit, such as power input, standby switch, screen input and output, external interfaces, and conduit interfaces.

[0064] Figure 3The operation flowchart of the power output controller. After connecting to the stoma catheter 1, the power output controller 4 passes the self-test and enters the energy output standby state. The doctor inserts the stoma catheter 1 into the target arterial location using the handle 2. The blood flow velocity sensor or blood pressure sensor set on the stoma catheter will detect the blood flow velocity and blood pressure data. Based on the detected data and the preset threshold range of blood flow velocity and blood pressure, the power output controller 4 can determine whether the predetermined blood vessel location has been reached and capture the blood vessel wall. When it is determined that the stoma catheter 1 has reached the target location, the power output controller 4 starts energy output. First, it checks whether the stoma catheter 1 is inside the human body. Because the arteriovenous fistula system is not only used for actual human vascular fistula surgery, but also for some in vitro experimental scenarios, such as product testing and in vitro vascular clamping training, the target location of the stoma catheter 1 may not be a real human blood vessel, but may be a simulated blood vessel device. When it is outside the human body, blindly activating the power output controller 4 may cause the electrode of the stoma catheter 1 to overheat, which may lead to the danger of life or property damage. Therefore, a special protection mechanism is added here. The specific principle is as follows: a temperature sensor is installed at the end of the stoma catheter 1. When the temperature sensor detects a significant difference between the ambient temperature and the body temperature, the power output controller 4 does not output energy and notifies the user via an alarm. This avoids the risk of injury or death caused by overheating of the external catheter. When the temperature sensor detects that the ambient temperature is close to the body temperature, the power output controller 4 outputs energy.

[0065] Furthermore, the power output controller 4 employs a PID closed-loop temperature control method, such as... Figure 4 As shown, through the combined adjustment of three parameters kp, ki, and kd, the fistula temperature at the tip of the fistula catheter 1 is raised from 30°C to the target temperature range of 370±30°C within 3 seconds. 370±30°C is the optimal temperature range for vascular fistula formation obtained by the present invention, which will not cause extensive damage to the blood vessels due to excessive temperature, nor will it affect the formation of the fistula due to excessively low temperature. Figure 5 This is the temperature rise curve regulated by PID control in this embodiment.

[0066] Figure 6This is a plan view of the head electrode of the stoma catheter 1. The stoma catheter 1 includes a first tube body 500 and a second tube body 600. One end of the first tube body 500 is located inside the handle housing, and the other end is located outside the handle housing and connected to a base 510. The base 510 has a first inclined surface, on which a proximal electrode plate 520 is mounted. The second tube body 600 passes through the first tube body 500, with its distal end located outside the first tube body 500 and connected to a head end 610. The head end 610 has a second inclined surface facing the first inclined surface, on which a distal electrode plate 620 is mounted. The first and second inclined surfaces are elliptical to each other, forming an angle of 22° with the axis. The reason for using this inclination angle in this embodiment is that the larger the inclination angle, the smaller the stoma area; the smaller the inclination angle, the smaller the vertical clamping force of the two electrode plates. Considering the above factors, the preferred inclination angle in this embodiment is about 22 degrees, which can ensure a larger stoma area clinically while ensuring that the clamping force of the electrode plates is not reduced.

[0067] Furthermore, in this embodiment, the proximal electrode 520 is configured as the heating end, and the distal electrode 620 is configured as the heated end. The maximum vertical distance between the end faces of the proximal and distal electrodes is approximately 3 mm (i.e., the maximum gap distance when the two electrodes are in the open state). The reason for using the above data in this embodiment is that the larger the gap, the easier it is to clamp the blood vessel wall, but the larger the gap, the higher the requirements for the electrode structure. Taking into account the above factors, this embodiment adds some operable margin to the thickness of the two blood vessel walls and considers electrode manufacturing factors, setting the maximum vertical distance between the end faces of the proximal and distal electrodes to approximately 3 mm. This distance dimension allows both blood vessel walls to be easily fitted into the gap, thus achieving clamping. Under the clamping of the tissue by the proximal and distal electrodes, the heat energy released by the proximal electrode penetrates the tissue to the distal electrode, forming a wrap-around fistula effect.

[0068] Furthermore, the heating electrode at the tip of the existing stoma catheter has structural design flaws, and the size and angle of the resulting arteriovenous fistula anastomosis can easily adversely affect blood flow. To overcome this defect, and considering the actual manufacturing requirements of the catheter, this embodiment optimizes the actual stoma area to be 3.3–7.9 mm², based on an electrode tilt angle of 22°. 2 Within the range. Figure 7 The design parameters for the two electrode areas are shown in the diagram. The stoma area is designed as an ellipse with a major axis of 4.3±0.5mm and a minor axis of 1.6±0.5mm. The welding area is designed as an elliptical ring with an outer ellipse having a major axis of 5.06±0.5mm and a minor axis of 1.8±0.5mm, and the inner ellipse being the stoma area. The maximum welding area of ​​the welding area shall not exceed 6.7mm². 2 The above parameters can achieve the optimal fistula opening without adversely affecting blood flow.

[0069] Furthermore, existing stoma systems cannot accurately measure the distance between the two electrode pads. Therefore, surgeons need to use ultrasound imaging or X-ray angiography during surgery to assist in determining whether the vessel wall clamping operation has been completed. This requires extensive surgical experience from the surgeon and is also prone to errors. This embodiment improves upon this by enabling precise measurement of the distance between the two electrode pads through the handle 2 and the power output controller 4, thereby accurately determining whether the vessel wall clamping operation has been completed.

[0070] For details, see Figure 8 Let A represent the initial position of the proximal electrode and An represent the final position. Then, the trajectory of the proximal electrode at any position after movement can be represented by A, A1, A2, A3…An. (See also...) Figure 9 The distal electrode is connected to the second tube body, and the proximal electrode is connected to the first tube body. Pushing the button causes the proximal electrode and the first tube body to move together along the axis towards the distal electrode, thereby changing the displacement A to An within the region. See also Figure 10 The button on the handle moves the slider containing the spring needle. The tip of the spring needle contacts the circuit board. Since the proximal electrode, the first tube, and the spring needle are linked, the displacement change between the proximal electrode and the distal electrode can be converted into the displacement change of the spring needle on the circuit board. The trajectory of the spring needle at any position after movement can be represented by C, C1, C2, C3...Cn. The range of motion of the spring needle corresponds proportionally to the relative distance between the two electrode plates. By detecting the range of motion of the spring needle, the relative distance between the distal electrode and the proximal electrode can be obtained.

[0071] For example, in Figure 11 The movable range of the spring pin in contact with the circuit board is evenly distributed into 26 interconnected conductive strips. Each conductive strip is connected to a 51Ω resistor. This means that when the spring pin contacts any conductive strip, the corresponding resistance value connected to the control circuit is fixed and unique. (See also...) Figure 12 The circuit diagram shown has the spring pin connected to the control circuit via the circuit board. Besides the series resistor formed by 26 conductive strips, there is a fixed resistor with a resistance of 1000Ω. In the control circuit, one end of the fixed resistor applies a 2.5V electromotive force to the spring pin, and the other end of the fixed resistor forms a voltage divider circuit with the spring pin. The conductive strips are arranged regularly to form an equivalent sliding rheostat. Figure 11 The relationship between the magnitude of the electromotive force obtained by the voltage divider circuit formed when the spring needle contacts any of the conductive strips and the overall control circuit is as follows:

[0072] φ n =φ×((Nn)×R) / (R0+(Nn)×R)

[0073] Where, φ n This represents the electromotive force obtained by the voltage divider circuit, where φ is a 2500mV electromotive force, R is a 51Ω resistor connected to the conductive strip, R0 is a 1000Ω fixed resistor, and n is the number of the conductive strip contacted by the spring needle, with n ranging from 1 to 26.

[0074] The power output controller calculates the conductive strip number contacted by the spring needle according to the above formula. Then, based on the contact strip number and the distance between the conductive strips, it calculates the actual travel distance of the spring needle. Finally, based on the ratio of the actual travel distance, the range of motion of the spring needle, and the distance between the two electrode plates, it calculates the distance between the distal and proximal electrode plates. Since the blood vessel wall at the target location in the human body typically has a fixed thickness range, comparing the distance between the distal and proximal electrode plates with the target blood vessel thickness range helps determine whether the clamping operation of the blood vessel wall has been completed.

[0075] The following is through Figure 13-14 This paper details the structural design of the fistula catheter and handle (i.e., the fistula device) in the arteriovenous fistula system of this embodiment.

[0076] The arteriovenous fistula device includes functional components such as a handle, a sliding component 200, an elastic pressure component 300, a stroke detection component 400, a first tube body 500, and a second tube body 600.

[0077] In this embodiment, a sliding button is installed on the outer side wall of the handle housing, and a cable 120 is provided inside the handle. The cable 120 is used to connect the control components and power supply, etc. The sliding button can be installed on the wider side wall of the handle or on the narrower side wall, and the sliding button can slide on the side wall of the handle.

[0078] In this embodiment, the sliding component 200 is slidably installed inside the handle. The sliding component 200 is connected to the sliding button. The connection method can be a fixed connection or a detachable connection. The sliding component 200 is configured to slide between an open position and a closed position under the action of the sliding button. When in the open position, the proximal electrode and the distal electrode are separated. When in the closed position, the proximal electrode and the distal electrode are in contact.

[0079] In this embodiment, the elastic pressure component 300 is connected to the inner wall of the handle and the sliding component 200 respectively, and is configured to apply a preload force to the sliding component 200 in the direction from the open position to the closed position. In this embodiment, the stroke detection component 400 is located inside the handle 100 and connected to the sliding component 200, and is configured to detect the sliding stroke of the sliding component 200. Its specific structure is given below.

[0080] The fistula catheter of this embodiment includes a first tube body 500 and a second tube body 600. In this embodiment, one end of the first tube body 500 is located inside the handle, and the other end is located outside the handle and connected to a base. The base is provided with a first inclined surface, and a proximal electrode is installed on the first inclined surface.

[0081] In this embodiment, the first tube 500 is made of a high-temperature resistant polymer, such as polyimide, polyetheretherketone, or silicone rubber. A printed marking strip on the outside indicates the sheath's withdrawal position during surgery. The first tube 500 is fixed to the base by adhesive bonding. The distance between the two electrode pads can be changed by pushing or pulling the first tube 500 and fixing the position of the second tube 600. The second tube 600 is made of nickel-titanium alloy or 316 stainless steel and is fixed to the proximal and distal electrode pads as a single unit by adhesive bonding or welding. The second tube 600, the proximal electrode pad, and the base all have a clearance fit, allowing relative movement. Pushing or pulling the tube and fixing the base position changes the distance between the two electrode pads. The inner hole of the second tube 600 can accommodate a guidewire for catheter insertion to a designated position during surgery.

[0082] In this embodiment, the radial dimension of the second tube 600 is smaller than that of the first tube 500. Therefore, the second tube 600 is inserted into the first tube 500, with its distal end located outside the first tube 500 and connected to a head end. The head end has a second inclined surface facing the first inclined surface, and a distal electrode plate 620 is installed on the second inclined surface. The height of the proximal surface of the head end 610 is lower than the height of the proximal surface of the base, and the two are at a preset distance. This preset distance creates a certain height difference between the head end and the base, preventing the catheter from getting stuck in human tissue or the sheath. A limiting structure is provided between the second tube 600 and the base to restrict their relative rotation, which can effectively prevent rotational misalignment between the second tube 600 and the base. In addition, an assembly positioning structure is provided between the second tube 600 and the head end to facilitate the connection and positioning between the second tube 600 and the head end.

[0083] Combined with appendix Figure 13 and attached Figure 14As shown, the sliding assembly 200 of this embodiment includes a slider 210 and an elastic positioning member 220. The slider 210 is connected to the elastic pressure assembly 300 and the stroke detection assembly 400 respectively. The first tube 500 passes through the slider 210 and is connected to the slider 210. The outer wall of the slider 210 is provided with a first positioning part 211 and a second positioning part 212. The elastic positioning member 220 is installed on the inner wall of the handle 100 and is configured to be able to position and cooperate with the first positioning part 211 and the second positioning part 212. Accordingly, the first positioning part 211 of this embodiment is a positioning groove adapted to the positioning bead, and the second positioning part 212 is a long strip positioning groove. The long strip positioning groove allows the elastic positioning member 220 to still generate a sliding tendency to make the two electrode plates stick together under the preload of the spring when the slider 210 slides to the closed position, thereby ensuring that a more stable minimum closing force can be provided.

[0084] Specifically, in this embodiment, the elastic positioning element 220 is a positioning bead. The positioning bead contains an elastic element (the specific structure is not shown in the figure). Its bottom has a small ball that can be pressed down and bounce back. When the small ball is subjected to a certain pressure, it is pressed into the positioning bead. When the pressure on the small ball is too small, it resets. Therefore, when the user pushes the sliding button to move the slider to the left, the user can feel the rebound pressure feedback given by the elastic positioning element 220.

[0085] In this way, when the sliding button 110 is pushed, the slider 210 slides to the left, and the proximal electrode moves to the distal electrode until it is closed. The button can no longer move forward. At this time, the small ball at the top of the positioning bead is instantly stuck into the long strip positioning groove and makes a "click" impact sound. That is, the elastic positioning element 220 is used to limit the stroke of the slider 210. The elastic positioning element 220 can produce a certain sound and feedback in both the first positioning part 211 and the second positioning part 212. It is not only simple in structure, but also easy to process, assemble and operate by the user.

[0086] There can be various specific structural forms for the elastic pressure assembly 300, such as combining it with... Figure 13 and attached Figure 14 As shown, in this embodiment, the elastic pressure assembly 300 and the sliding assembly 200 are coaxially arranged. The assembly may include a mounting base 310, an elastic element 320, two washers 330, and a nut 340. The mounting base 310 is disposed on the inner wall of the arm. One end of the spring near the sliding assembly 200 is connected to the mounting base 310 via a washer 330. The connection between the spring and the washer 330 on the right side of the figure can be either abutment or fixed connection. The other end of the spring is connected to the first tube 500 via another washer 330 and a nut 340. The left end of the slider 210 passes through the spring and is connected to the nut 340. Figure 13 and Figure 14When the sliding component 200 is in a compressed state, it can move from the open position to the closed position when it moves to the left. This causes the end of the first tube 500 with the proximal electrode to move towards the distal electrode, thus achieving docking of the proximal and distal electrode and clamping the artery and vein. When the device detects that the two electrodes are closed, it excites energy in front of the two electrodes to create a fistula in the artery and vein.

[0087] During the above process, since the spring is compressed in the open position, it provides a certain elastic restoring force to the sliding assembly 200. In the closed state, this elastic restoring force is only partially weakened, but it still ensures a minimum closing force when the proximal and distal electrode plates are closed, preventing the two electrodes from opening due to the user releasing the handle during the closing process. In this way, by applying prestress to the elastic element 320 in the open position, the elastic element 320 deforms. When switching from the open to the closed position, the elastic element 320 maintains this deformation, thus providing a preload force to the sliding assembly 200. This not only facilitates user operation but also prevents the closed electrode plates from opening again.

[0088] In this embodiment, the aforementioned structure of the fistula catheter and handle, by adding a stroke detection module, can accurately detect the relative displacement of the head electrode, thereby accurately determining whether the opening and closing structure of the fistula catheter tip is completely closed. By setting a pre-tightening structure in the handle, the clamping electrode will not loosen even if the external force disappears after the fistula catheter tip is closed, ensuring effective formation of an endovascular fistula.

[0089] The following is through Figure 15-17 This paper details the features of the head clamping structure of the fistula catheter in the arteriovenous fistula system of this embodiment.

[0090] Combined with appendix Figure 15 As shown, preferably, a boss 621 is provided on the inclined surface of the distal electrode 620 facing the head end 610. The boss 621 facilitates laser welding of the distal electrode 620 and the inclined surface of the head end 610. Laser continuous welding or spot welding can be performed to prevent the head end 610 from falling off when compressing blood vessels and improve product reliability.

[0091] Combined with appendix Figure 16 As shown, preferably, the first tube body 500 and the head end 610 are respectively provided with sensors 700 for detecting blood flow or pressure. The sensors 700 are used to detect the blood flow or pressure in the arteries and veins, thereby determining whether the two electrode pads have successfully captured the arterial and venous vessel walls during the interventional procedure.

[0092] More preferably, in this embodiment, the tip 610 and the base are filled with microbubbles (not shown in the figure), and dotted pits (not shown in the figure) are provided on the outer surface of the tip 610 and the base. The microbubbles reduce the acoustic impedance of the tip 610 and the base, thereby increasing the ultrasonic reflection intensity. The dotted pits increase the imaging of the tip 610 and the base under ultrasound. In addition, to increase the acoustic impedance of the material itself, barium sulfate, tungsten, or other high acoustic impedance particles can be doped into the polymer material of the tip 610 and the base to increase the ultrasonic reflection intensity. Alternatively, an imaging metal braided layer can be placed in the inner hole of the catheter tip 610 and the inner hole of the base. The material can be stainless steel, nickel-titanium alloy, or platinum-iridium alloy. In addition, the roughness of the outer surface of the tip 610 and the base can be increased to increase ultrasonic reflection in all directions.

[0093] Combined with appendix Figure 17 As shown, the base of this embodiment is equipped with a heating element 513 and a thermocouple. The heating element 513 is made of a high-resistivity metal, laser-cut from a 0.05-0.2mm thin metal sheet, and then coated with an insulating layer with a thickness of 1-10 micrometers. When current passes through the heating element 513, heat is generated and transferred to the electrode plates via thermally conductive adhesive, acting on the walls of arteries and veins. Specifically, the heating element 513 is an elliptical, hollow, filament-like structure with repeated bends. The major and minor axes of its outer ellipse are slightly smaller than the groove structure of the base. The hollow elliptical structure allows the second tube 600 to pass through smoothly. The width of the single filament ranges from 0.02-0.05mm. The heating element 513 has wires exiting from one side, which can be led out from one hole in the base. The other hole in the base can be used to lead out the thermocouple wires. The thermocouple is used to detect the temperature of the proximal electrode plate being heated.

[0094] The above description is merely a preferred embodiment of the present invention. Those skilled in the art should understand that the scope of disclosure involved in the present invention is not limited to the technical solutions formed by specific combinations of the above-described technical features, but should also cover other technical solutions formed by arbitrary combinations of the above-described technical features or their equivalents without departing from the above-described concept. For example, technical solutions formed by substituting the above-described features with (but not limited to) technical features with similar functions disclosed in the present invention.

Claims

1. An arteriovenous fistula system, characterized in that, include: Fistula catheter, handle, power transmission line and power output controller; The stoma catheter includes a first tube and a second tube. One end of the first tube is located inside the housing of the handle, and the other end is located outside the housing of the handle and connected to a base. The base has a first inclined surface, and a proximal electrode is installed on the first inclined surface. The second tube passes through the first tube, and its distal end is located outside the first tube and connected to a head end. The head end has a second inclined surface facing the first inclined surface, and a distal electrode is installed on the second inclined surface. The handle includes a housing, a sliding component, an elastic pressure component, and a stroke detection component; a sliding button is installed on the side wall of the housing, the sliding component is slidably installed inside the housing, and is configured to slide between an open position and a closed position under the action of the sliding button; the elastic pressure component is connected to the inner wall of the housing and the sliding component respectively, and is configured to apply a preload force to the sliding component in the direction from the open position to the closed position; The stroke detection component is connected to the sliding component and is configured to detect the sliding stroke of the sliding component; The first tube or the second tube is connected to the sliding assembly. The sliding assembly slides from the open position to the closed position, driving the spaced proximal electrode and the distal electrode to a contact state. One end of the power transmission line is connected to the power output controller, and the other end is electrically connected to the first or second tube inside the handle's housing. The power output controller is used to determine whether the stent catheter has successfully captured the arterial and venous vessel walls based on the blood flow rate or blood pressure detected by the sensors installed on the first and second tubes; to calculate the distance between the proximal electrode and the distal electrode based on the measurement value of the sliding component by the stroke detection component; and to determine whether to activate energy output to heat the proximal electrode and / or the distal electrode based on the detection value of the temperature sensor installed on the first or second tube. The sliding assembly includes a slider and an elastic positioning element; the slider is connected to the elastic pressing assembly and the stroke detection assembly respectively, the first tube or the second tube is connected to the slider, and the outer wall of the slider is provided with a first positioning part and a second positioning part; The elastic positioning member is installed on the inner wall of the handle housing and is configured to be able to position and cooperate with the first positioning part and the second positioning part. The elastic pressure assembly includes a mounting base and an elastic element. The mounting base is fixedly connected to the inner wall of the handle. One end of the elastic element is connected to the mounting base, and the other end is connected to the sliding assembly. When the sliding assembly is between the open position and the closed position, the elastic element is compressed and has an elastic force in the direction from the open position to the closed position. The elastic positioning element is a positioning bead, the first positioning part is a positioning groove adapted to the positioning bead, and the second positioning part is a long strip-shaped positioning groove. The long strip-shaped positioning groove allows the elastic positioning element to still generate a sliding tendency that makes the two electrode pieces stick together under the action of the pre-tightening force of the elastic element when the slider slides to the closed position, thereby ensuring that a more stable minimum closing force can be provided.

2. The arteriovenous fistula system according to claim 1, characterized in that: The stroke detection component includes a detection circuit, which includes a DC voltage source, a switch, a fixed resistor, and a sliding rheostat connected in series. The two ends of the sliding rheostat are connected in parallel with a voltmeter. The sliding rheostat includes multiple conductive strips and a spring pin. The multiple conductive strips are evenly spaced in a preset direction in the detection area. Each conductive strip has the same resistance and is connected in series with each other. One end of the spring pin is installed on the sliding assembly and slides with the sliding assembly, and the other end is provided with a pointed tip that abuts against the conductive strip. The power output controller is used to calculate the sequential number of the conductive strip currently pointed to by the tip of the spring needle based on the detected voltage value of the voltmeter, the resistance value of each conductive strip, the total number of conductive strips, the fixed resistance value, and the electromotive force of the DC voltage source; to calculate the actual travel distance of the spring needle based on the sequential number of the conductive strip currently pointed to by the tip of the spring needle and the interval distance between the conductive strips; and to determine the distance between the distal electrode and the proximal electrode based on the proportional relationship between the actual travel distance of the spring needle, the movable range of the spring needle, and the distance between the two electrode plates.

3. The arteriovenous fistula system according to claim 2, characterized in that, The power output controller calculates the sequential numbering of the conductive strips contacted by the tip of the spring needle according to the following formula: = in, This indicates the voltage value detected by the voltmeter. The electromotive force of the DC voltage source. The resistance value for each conductive strip, For fixed resistor values, The sequence numbering of the conductive strips that the tip of the spring needle contacts. This represents the total number of conductive strips.

4. The arteriovenous fistula system according to claim 1, characterized in that: The proximal electrode plate is the heating end, and the distal electrode plate is the heated end; Both the distal and proximal electrode pads are elliptical in shape. Each electrode pad includes an elliptical stoma area and an elliptical annular welding area. Both electrode pads form a 22° angle with the axis of the stoma catheter, and the maximum vertical distance between the end faces of the two electrode pads is 3 mm.

5. The arteriovenous fistula system according to claim 4, characterized in that: The major axis of the stoma region is 4.3±0.5 mm, the minor axis is 1.6±0.5 mm, and the area of ​​the stoma region is 3.3-7.9 mm. The major axis of the outer ellipse of the welding area is 5.06±0.5mm, and the minor axis is 1.8±0.5mm. The inner ellipse of the welding area is the stoma area, and the maximum welding area of ​​the welding area does not exceed 6.7 mm. .

6. The arteriovenous fistula system according to claim 4, characterized in that: The base is provided with a heating element corresponding to the welding area. The heating element is an elliptical ring structure that is repeatedly bent. The two leads of the heating element are electrically connected to the power transmission line through the inside of the first tube.

7. The arteriovenous fistula system according to claim 6, characterized in that, The heating element is made of a high resistivity metal with a thickness of 0.05-0.2 mm.

8. An arteriovenous fistula system according to claim 6 or 7, characterized in that: The base is equipped with a thermocouple for detecting the temperature of the heating element. The power output controller is used to control the temperature of the heating element to maintain at the target temperature value based on the temperature detection value of the thermocouple.

9. The arteriovenous fistula system according to claim 8, characterized in that: The target temperature is 370±30℃.

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