Thrombus aspiration system and control method thereof

Abstract

This invention relates to a thrombus aspiration system and its control method, comprising: an aspiration catheter having an aspiration cavity and a distal end having an opening; an electrode assembly disposed at the opening, the electrode assembly contacting an object at the opening and measuring its impedance value; and a controller acquiring the impedance value and determining the type of the object at the opening based on the impedance value. This thrombus aspiration system can determine the opening state of the aspiration catheter according to the type of object at the opening and adjust the aspiration strategy accordingly, thereby reducing blood loss and improving aspiration efficiency.

Description

Technical Field

[0001] This invention relates to the field of medical devices, and in particular to a thrombus aspiration system and its control method. Background Technology

[0002] With an aging population and changing lifestyles, thromboembolic diseases are increasingly becoming a major global health problem, even evolving into one of the leading causes of death worldwide. Current conventional treatments include medication and surgery. Thromboablation is a common surgical treatment method. In the actual procedure, a suction catheter is inserted into the blood vessel and guided close to the thrombus. Negative pressure is then used to extract the thrombus. Clinical trials have shown high rates of recanalization, and the procedure is simple and quick.

[0003] However, currently available aspiration systems can only roughly determine the location of the thrombus through methods such as DSA and ultrasound after entering the body, and cannot identify the condition of the aspiration catheter opening. This results in low thrombus aspiration efficiency and increased surgical risks. For example, when the opening of the aspiration catheter is not in contact with the thrombus, negative pressure aspiration will cause a large amount of normal blood to be lost, leading to increased blood loss in the patient. The patient will find it difficult to maintain normal blood volume and blood pressure, and in severe cases, a blood transfusion may be required. Summary of the Invention

[0004] Therefore, it is necessary to provide a thrombus aspiration system to address the above problems, comprising: an aspiration catheter having an aspiration cavity and a distal end having an opening; an electrode assembly disposed at the opening, the electrode assembly contacting an opening contact and measuring its impedance value; and a controller acquiring the impedance value and determining the type of the opening contact based on the impedance value.

[0005] Furthermore, the electrode assembly includes a first power electrode, a first measuring electrode, a second power electrode, and a second measuring electrode arranged in a circular pattern, wherein the first power electrode and the second power electrode are arranged radially opposite to each other, the first measuring electrode and the second measuring electrode are arranged radially opposite to each other, and adjacent electrodes are connected by an insulator.

[0006] Furthermore, the electrode assembly measures at least three impedance values ​​of the tube contact material under AC power at different frequencies, and the controller obtains the intracellular fluid resistance R1, cell membrane capacitance C, and plasma resistance R0 based on the at least three impedance values.

[0007] Furthermore, the controller determines the biometric index f based on the intracellular fluid resistance R1, cell membrane capacitance C, and plasma resistance R0, where f = w1R0 + w2R1 + w3C, and w1, w2, and w3 are weighting coefficients. The controller then determines the type of material in contact with the tube opening based on the biometric index f.

[0008] Furthermore, the controller determines the numerical range to which the biometric index f belongs based on the value of the biometric index f, and the controller determines the type of the contact object at the nozzle based on the numerical range to which the biometric index f belongs.

[0009] Furthermore, it also includes a negative pressure control valve, the proximal end of which is connected to a vacuum source and the distal end of which is connected to the suction chamber; the controller applies a square wave voltage to drive the negative pressure control valve, and the controller adjusts the duty cycle of the square wave voltage according to the type of object contacted by the nozzle.

[0010] Furthermore, the controller adjusts the period of the square wave voltage according to the type of contact object at the nozzle.

[0011] Furthermore, the suction conduit also has a high-pressure chamber, which is isolated from the suction chamber; it also includes a booster motor and a high-pressure pump, the booster motor drives the high-pressure pump to move, and the high-pressure chamber is connected to the output end of the high-pressure pump; the controller adjusts the speed of the booster motor according to the type of object contacted by the conduit.

[0012] This invention also relates to a control method for a thrombus aspiration system, comprising:

[0013] Obtain at least three impedance values ​​of the contact material at the nozzle of the suction catheter at different frequencies;

[0014] Based on the at least three impedance values, determine the intracellular fluid resistance R1, the cell membrane capacitance C, and the plasma resistance R0;

[0015] Based on the intracellular fluid resistance R1, cell membrane capacitance C, and plasma resistance R0, the biological characteristic index f is determined, f = w1R0 + w2R1 + w3C, where w1, w2, and w3 are weighting coefficients.

[0016] The numerical range to which the biometric index f belongs is determined based on the index.

[0017] The type of material in contact with the nozzle is determined based on the numerical range of the biometric index f.

[0018] Furthermore, the thrombus aspiration system includes a negative pressure control valve connected between the vacuum source and the aspiration catheter, and the duty cycle of the square wave voltage driving the negative pressure control valve is adjusted according to the type of material contacted by the catheter port.

[0019] The technical solution of the present invention has the following beneficial effects: The thrombus aspiration catheter system of the present invention can identify the type of contact object at the tube opening of the aspiration catheter, thereby identifying the specific state of the tube opening and adjusting the aspiration strategy according to the specific state, thereby reducing ineffective aspiration and increasing effective aspiration, reducing blood loss, improving thrombus aspiration efficiency, and avoiding damage to normal tissues such as blood vessel walls. Attached Figure Description

[0020] Figure 1 This is a diagram showing the overall composition of a thrombus aspiration system.

[0021] Figure 2 This is a diagram showing the overall structure of the aspiration catheter;

[0022] Figure 3 This is a partial cross-sectional view of the distal side of the aspiration catheter;

[0023] Figure 4 This is a structural diagram of the electrode assembly;

[0024] Figure 5 This is a diagram of the overall outer tube structure of the hand controller;

[0025] Figure 6 This is a structural diagram of the hand controller after part of the housing has been removed.

[0026] Figure 7 This is a cross-sectional view of the hand controller;

[0027] Figure 8 This is a schematic diagram of the structure after the flow switch is turned off;

[0028] Figure 9 This is a diagram showing the overall composition of the host computer.

[0029] Figure 10 This is a diagram showing the external structure of the main unit;

[0030] Figure 11 a-11d is a schematic diagram of the pipe opening in contact with different types of pipe opening contact materials;

[0031] Figure 12 The circuit diagram is for the electrode assembly.

[0032] Figure 13 A flowchart for identifying the types of materials that come into contact with the nozzle;

[0033] Figure 14 This is a schematic diagram of a square wave voltage.

[0034] Figure 15 The control flowchart for the thrombus aspiration system; Detailed Implementation

[0035] To make the above-mentioned objects, features, and advantages of the present invention more apparent and understandable, specific embodiments of the present invention will be described in detail below with reference to the accompanying drawings. Many specific details are set forth in the following description to provide a thorough understanding of the present invention. However, the present invention can be practiced in many other ways different from those described herein, and those skilled in the art can make similar modifications without departing from the spirit of the present invention. Therefore, the present invention is not limited to the specific embodiments disclosed below.

[0036] It should be noted that when an element is referred to as being "fixed to" or "set on" another element, it can be directly on the other element or there may be an intervening element. When an element is considered to be "connected to" another element, it can be directly connected to the other element or there may be an intervening element. The terms "upper," "lower," "left," "right," and similar expressions used to indicate orientation are for illustrative purposes only and do not represent the only possible implementations. Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. The terminology used herein in the specification of this invention is for the purpose of describing particular embodiments only and is not intended to limit the invention. The term "and / or" as used herein includes any and all combinations of one or more of the associated listed items.

[0037] It should be noted that, for medical devices, the end of the medical device that is relatively closer to the operator is generally called the "proximal end," and the end that is relatively farther from the operator is called the "distal end." Based on this principle, the "proximal end" and "distal end" of any component of the delivery system are defined. "Proximal end" and "distal end" are only used to describe the orientation and do not refer to the end face of the proximal end or the end face of the distal end. "Axial axis" or "longitudinal axis" refers to the direction parallel to the line connecting the center of the distal end and the center of the proximal end of the medical device. "Radial axis" or "lateral axis" refers to the direction perpendicular to the axial direction.

[0038] First Embodiment

[0039] See Figure 1The diagram shows the overall composition of the thrombus aspiration system 1 in this embodiment. The thrombus aspiration system 1 includes an aspiration unit 100, a hand controller 200, an aspiration catheter 300, and a high-pressure pump 400. The aspiration unit 100 is equipped with a high-pressure power source 140, which is connected to the high-pressure pump 400, transmitting power from the high-pressure power source 140 to the high-pressure pump 400 to drive its movement. The proximal end of the hand controller 200 is connected to the aspiration unit 100 (including mechanical and electrical connections), and the distal end is connected to the aspiration catheter 300. The aspiration unit 100 contains a vacuum pump 130, which serves as a negative pressure source to provide negative pressure for the entire aspiration system 1. In other embodiments, a negative pressure tank can also be used as the negative pressure source. The negative pressure control valve 120 is a control valve connected between the negative pressure source and the aspiration catheter 300, used to control the negative pressure output of the aspiration unit 100. When the negative pressure control valve 120 is open, the suction catheter 300 is connected to the vacuum pump 130, and negative pressure can be generated at the distal end of the suction catheter 300, thereby enabling the suction of the thrombus. When the negative pressure control valve 120 is closed, the connection between the suction catheter 300 and the vacuum pump 130 is cut off. At this time, the negative pressure generated by the vacuum pump 130 cannot be transmitted to the suction catheter 300, and negative pressure cannot be generated at the distal end of the suction catheter 300, thus stopping the suction operation. The controller 110 is the control unit of the thrombus suction system 1. It is electrically connected to the vacuum pump 130, the negative pressure control valve 120, and the high-voltage power source 140 to control the entire suction unit 100.

[0040] See Figure 2-3The structure of the aspiration catheter 300 is described below. The aspiration catheter 300 includes a main tube 310, a first side tube 330, and a second side tube 320. The main tube 310 extends along its axis and contains a mutually isolated aspiration chamber 311 and a high-pressure chamber 312. Its distal end has a port 314. The port 314 serves as the working port, through which the contact material 800 is aspirated, and the contact material 800 enters the aspiration chamber 311. In this embodiment, the substance that the aspiration catheter 300 contacts during aspiration in a blood vessel is referred to as the contact material 800, which enters the aspiration chamber 311 due to negative pressure suction. The proximal end of the first side tube 330 is connected to the output end of the high-pressure pump 400, and its distal end extends to connect with the high-pressure chamber 312 of the main tube 310, thereby allowing the injection of high-pressure liquid into the high-pressure chamber 312. The proximal end of the second side tube 320 is connected to the output end of the vacuum pump 130, and the distal end extends to connect with the suction chamber 311 of the main tube 310, thereby delivering negative pressure to the suction chamber 311 to generate negative pressure at the distal opening of the suction chamber 311, thus achieving thrombus suction. The distal end face of the high-pressure chamber 312 is closed, and the distal sidewall has a nozzle (not shown in the figure), from which high-pressure liquid can be ejected. In the actual thrombus suction process, when the tube opening 314 contacts the thrombus, due to the negative pressure in the suction chamber 311, the thrombus will be sucked into the suction chamber 311 from the tube opening 314. At the same time, the high-pressure liquid forms a high-pressure jet through the nozzle on the high-pressure chamber 312, which cuts the thrombus that has entered the suction chamber 311. Under the combined action of negative pressure suction and high-pressure jet, the thrombus is torn into fragments and sucked into the suction catheter 300, thereby achieving efficient suction and preventing blockage.

[0041] See Figure 2 , 4 As shown, the distal end of the suction catheter also has an electrode assembly 313, which forms at least a portion of the port 313. The electrode assembly 313 includes four electrode plates arranged circumferentially, with adjacent electrode plates connected by an insulator 3131, thus fixing the entire electrode assembly 313 in a ring shape to the distal end face of the suction catheter 300. Specifically, the electrode assembly 313 includes a first power electrode E1, a first measuring electrode E2, a second power electrode E3, and a second measuring electrode E4 arranged circumferentially in sequence. The first power electrode E1 and the second power electrode E3 are radially opposite to each other, forming a set of power electrodes, and the first measuring electrode E2 and the second measuring electrode E4 are radially opposite to each other, forming a set of measuring electrodes.

[0042] See Figure 2 , 5As shown in Figure -8, the structure of the hand controller 200 will be described. The hand controller 200 is an intermediate connecting carrier disposed between the vacuum pump 130 and the aspiration catheter 300 of the main unit 100. The operator can control the thrombus aspiration system 1 through the hand controller 200. The hand controller 200 has a housing 200a, and the housing 200a contains a control board 210, a hand switch 220, a pressure sensor 230, and a flow switch 270.

[0043] The housing 200a has a distal hose 260 and a proximal hose 250 and cable 290. The proximal end of the proximal hose 250 is connected to the vacuum pump 130, and the distal end extends into the housing 200a. The distal end of the distal hose 260 is connected to the suction conduit 300, and the proximal end extends into the housing 200a. The portions of the distal hose 260 and the proximal hose 250 located within the housing are connected via a pipe adapter 240. The pressure sensor 230 and the manual switch 220 are integrated on the control board 210 and connected to the main unit 100 via the cable 290 for power supply and real-time communication. The pipe adapter 240 is a tee connector, which connects the proximal hose 250 and the distal hose 260 on one side, and also has a branch hose 280 on the other side. The hose 280 is connected to the pressure sensor 230, thereby enabling pressure measurement within the hose 280. Therefore, in this embodiment, the pressure sensor 230 is coupled to the distal hose 260 and the proximal hose 250 via the pipe adapter 240 to monitor the pressure on the proximal side of the suction tubing 300. In this embodiment, the pressure sensor 230 is a negative pressure sensor, which can detect the negative pressure at the proximal end of the suction tubing 300 and feed it back to the host 100 in real time. The host 100 can inform the operator of the current negative pressure status through a display screen, indicator lights, sound, or digital tube.

[0044] The flow switch 270 is an electromagnetically controlled switch, comprising an electromagnet 271 and a spring magnet 272. The ends of the electromagnet 271 and the spring magnet 272 are connected. A portion of the distal hose 260 is located between the electromagnet 271 and the spring magnet 272. The electromagnet 271 and the spring magnet 273 can move close together to clamp the distal hose 260. See also... Figure 7 As shown, when electromagnet 271 is not energized, flow switch 270 is in the open state. At this time, because electromagnet 271 has no electromagnetic force, it will not attract the spring magnet 273, and neither electromagnet 271 nor spring magnet 273 will clamp the distal hose 260. (See also...) Figure 8 As shown, when the electromagnet 271 is energized, the flow switch is in the pipe wall state. The electromagnet 271 generates a magnetic force that attracts the spring magnet 273. This magnetic force will flatten the distal hose 260, at which time the distal conduit 260 is in the cut-off state.

[0045] The manual switch 200 is used to control the operation of the entire thrombus aspiration system 1. When the manual switch 200 is not triggered, the flow switch 270 is closed, the distal catheter 260 is in the cut-off state, and the connection between the aspiration catheter 300 and the main unit 100 is disconnected. When the manual switch 200 is pressed, the flow switch 270 is opened, the distal catheter 260 is in the conducting state, the connection between the aspiration catheter 300 and the main unit 100 is restored, and the thrombus aspiration system 1 starts working and performs related initialization work. The manual switch 200 is the master control switch of the thrombus aspiration system 1; the thrombus aspiration system 1 will only start when it is in the triggered state.

[0046] See Figure 9-10The structure of the main unit 100 is described below. The main unit 100 includes a controller 110, a negative pressure control valve 120, a vacuum pump 130, and a high-voltage power source 140. The vacuum pump 130 and the controller 110 are powered by a power module 110c. When the power switch 100a is turned on, the power module 100c starts. Specifically, the power interface 100b is connected to the mains power supply and then electrically connected to the power module 100c via the power switch 100a. The vacuum pump 130 is the vacuum source of the thrombus aspiration system 1 in this embodiment, providing negative pressure vacuum for the entire system to achieve subsequent aspiration actions. The vacuum pump 130 is coupled to the negative pressure output interface 1130 and the negative pressure adjustment button 1120 via a gas adapter 1100. The negative pressure adjustment button 1120 can control the maximum negative pressure output of the vacuum pump 130 and can also be used as a pressure relief valve. The negative pressure output interface 1130 is connected to the bottom of the collection tank 160 (not shown in the figure). The collection tank 160 is connected to the negative pressure control valve 120 through a connecting conduit (not shown in the figure; in this embodiment, other conduits besides the suction conduit are collectively referred to as connecting conduits). The negative pressure control valve is also connected to the suction conduit 300. In this embodiment, the vacuum pump 130 is controlled by the negative pressure control valve 120 to output negative pressure to the suction conduit 300. The controller 110 can periodically open and close the negative pressure control valve 120 to realize the periodic opening and closing of the suction action. The high-pressure power source 140 includes a booster motor 140a and a transmission mechanism 140b. The booster motor 140a is a common electric motor, such as a DC motor, AC motor, or stepper motor. Its output shaft is connected to the transmission mechanism 140b, which converts the rotational motion of the output shaft of the booster motor 140a into reciprocating linear motion. The transmission mechanism 140b is connected to the high-pressure pump through the high-pressure pump head mounting port 150. A current sensor 170 on the booster motor 140a monitors its operating current in real time and feeds it back to the controller 110. The controller 110 adjusts the speed, torque, etc., of the booster motor 140a. The display screen 190 displays the operating status or monitoring data of the main unit 100, such as the current measured by the current sensor 170 and the pressure value measured by the pressure sensor 230 on the hand controller 200, facilitating real-time monitoring of the thrombus aspiration system 1 by the operator. The hand controller interface 180 connects to the hand controller 200 for real-time communication, receiving signals from the pressure sensor 230 on the hand controller 200 and transmitting them to the controller 110.

[0047] When the aspiration catheter 300 performs aspiration in a blood vessel, its port 314 comes into contact with different substances. Since the contact substance 800 is drawn into the aspiration catheter 300 under negative pressure after passing through port 314, the type of contact substance 800 directly determines the type of substance subsequently aspirated by the aspiration catheter 300. The contact substance 800 mainly includes four types: complete blood 800a, blood-thrombus mixture 800b, complete thrombus 800c, and vessel wall 800d.

[0048] For complete blood 800a, see Figure 11 As shown in Figure a, when the orifice 314 is completely immersed in blood and not in contact with a thrombus, or only in contact with a small amount of free thrombus in the blood (thrombus volume to blood volume ratio less than 10%), the aspiration catheter 300 aspirates healthy, clot-free blood or blood without vascular occlusion clots. Healthy blood is defined as blood with a sufficiently low proportion of cross-linked fibrin, preventing it from fully integrating to cause ischemia or other similar vascular occlusion. When the orifice is in contact with pure blood, the flow aspirated by the aspiration catheter 300 is essentially liquid. For blood-thrombus mixture 800b, see [reference needed]. Figure 11 As shown in b, the portion of the cannula 314 comes into contact with a thrombus in the blood vessel. At this point, the aspiration catheter 300 aspirates a mixture of blood and thrombus, and the flow aspirated from the catheter is a solid-liquid mixture. For complete thrombus 800c, see [reference needed]. Figure 11 As shown in Figure c, when the nozzle 314 is in complete contact with the thrombus, the aspiration catheter 300 aspirates either a complete thrombus or a thrombus containing only a small amount of blood (the ratio of blood volume to thrombus volume is less than 10%). The aspirated fluid is essentially solid. For the vessel wall, see [reference needed]. Figure 11 As shown in d, the nozzle 314 is directly facing the blood vessel wall and the tissue on the blood vessel wall is suctioned. If the suction force is too large, it may damage the blood vessel wall.

[0049] The impedance-frequency characteristics of blood indicate that for low-frequency (below 100kHz) or high-frequency (above 5MHz) test signals, blood exhibits pure resistance, while in the intermediate frequency range, it exhibits complex impedance. At this point, as the test signal frequency increases, the blood impedance gradually decreases, and cells can no longer be considered insulating particles. Based on the three-element blood model, the impedance calculation formula is as follows:

[0050]

[0051] In the above formula, Z represents blood impedance, R1 represents intracellular fluid resistance, C represents cell membrane capacitance, R0 represents plasma resistance, ω is the AC frequency, and j is the imaginary unit.

[0052] Considering that different types of catheter port contacts have different impedances, and the intracellular fluid resistance value R1, cell membrane capacitance value C, and plasma resistance value R0 that constitute their impedance are different, it is possible to identify each type of catheter port contact based on the values ​​of R1, C, and R0, and then determine its specific type. Then, the aspiration action of the thrombus aspiration system 1 can be adjusted according to the specific type of catheter port contact 800, thereby reducing blood loss and improving thrombus aspiration efficiency.

[0053] See Figure 12 As shown, this embodiment uses the Kelvin four-wire detection method to measure the impedance value Z of the conduit orifice contact. The first power electrode E1 and the second power electrode E3 are respectively connected to the two ends of the conduit orifice contact 800. The ammeter 600, the first power electrode E1, the conduit orifice contact 800, and the second power electrode E3 are connected in series to the two phase points of the AC power supply 500 to form a circuit. Additionally, the two ends of the voltmeter 700 are connected to the two ends of the conduit orifice contact 800 through the first measuring electrode E2 and the second measuring electrode E4 to form a second circuit. If the current measured by the ammeter 600 is I(t) and the voltage measured by the voltmeter 700 is U(t), then the impedance Z(t) of the conduit orifice contact 800 is Z(t) = U(t) / I(t). Therefore, in this embodiment, by setting the electrode group 313 at the conduit 314, the impedance of the conduit orifice contact 800 is measured using the Kelvin four-wire detection method.

[0054] See Figure 13 The diagram shows a flowchart for identifying the specific type of catheter contact 800. Specifically, multiple impedance values ​​Z are measured at different current frequencies ω of the AC power supply 500 (at least three impedance values ​​Z1, Z2, and Z3 are measured at three different AC power supplies 500 frequencies). Based on the measured impedance values ​​at the corresponding frequencies, the specific values ​​of R0, R1, and C of the catheter contact 800 can be calculated using the impedance calculation formula. Once the values ​​of R0, R1, and C are determined, the biometric index f is calculated.

[0055] f = w1R0 + w2R1 + w3C

[0056] Among them, w1, w2, and w3 are weighting coefficients, obtained in advance through experiments, for example, by fitting using the least squares method. After obtaining the biometric index f, its numerical range is determined based on its specific value. In this embodiment, the numerical ranges correspond one-to-one with the four types of the contact material 800 at the tube opening, including four ranges. Specifically, this numerical range includes the complete blood range A1 = [ [a1,a2], Blood-thrombus mixture interval A2 = [ [a3,a4]、Complete thrombosis interval A3= [[a5, a6], and the vessel wall interval A4 = [a7, a8]. A1, A2, A3, and A4 are pre-determined experimentally and stored in the controller's storage module. For example, for A1, the R0, R1, and C values ​​corresponding to complete blood can be obtained experimentally. Based on R0, R1, and C, the specific biometric index f can be obtained, thus determining the minimum value a1 and the maximum value a2 of this interval. When f is in the A1 interval, it indicates that the tube contact material 800 is complete blood; when f is in the A2 interval, it indicates that the tube contact material 800 is a blood-thrombus mixture; when f is in the A3 interval, it indicates that the tube contact material 800 is a complete thrombus; and when f is in the A4 interval, it indicates that the tube contact material 800 is the vessel wall.

[0057] See Figure 14 As shown, the controller 110 applies a square wave voltage to the negative pressure control valve 120 to control the opening of the negative pressure control valve 120. The square wave voltage is a periodically changing voltage. Within one period T, it includes a high-level voltage Vmax with a width of T1 and a low-level voltage Vmin. When the high-level voltage Vmax is applied to the negative pressure control valve 120, the negative pressure control valve 120 opens, and the suction conduit 300 obtains negative pressure, thus enabling suction. When the low-level voltage Vmin is applied to the negative pressure controller 120, the negative pressure control valve 120 closes, and the suction conduit 300 loses negative pressure, terminating the suction action. The duty cycle refers to the proportion of the energized time relative to the total time within one pulse cycle. In this embodiment, the duty cycle D is the ratio of T1 to T. A larger duty cycle D means that the square wave voltage remains at the high-level voltage Vmax for a longer period within one period T, and therefore the negative pressure control valve 120 remains open for a longer period.

[0058] See Figure 15 The control process of the thrombus aspiration system 1 is described below. In this embodiment, the controller 110 adjusts the duty cycle D and period T of the square wave voltage according to the type of contact object 800 at the aspiration port, and adjusts the rotational speed of the booster motor 140a, thereby changing the aspiration strategy according to the specific state of the port 314 of the aspiration catheter 300, thereby reducing blood loss, improving aspiration efficiency, and reducing damage to the blood vessel wall.

[0059] Specifically, when the system is ready, the system will perform initialization operations. At this time, the duty cycle of the square-wave voltage is set to the initial value D0, and the initial value of the working cycle is set to T0. At this time, the booster motor is turned off, the high-pressure pump 400 stops working, and there is no high-pressure liquid in the high-pressure chamber 312 of the suction catheter 300. When the manual switch 220 is not triggered, the suction catheter 300 is in a cut-off state and cannot perform suction. When the manual switch is triggered, the flow switch will open to make the distal catheter conductive, and at this time, the suction catheter 300 performs suction. At this time, the square-wave voltage applied by the controller to the negative pressure control valve works with a duty cycle of D0 and a working cycle of T0. The negative pressure control valve intermittently "opens - closes" with a duty cycle of D0 and a working cycle of T0. After the data such as the impedance of the object in contact with the nozzle are collected, they are transmitted to the controller, and the controller identifies the type of the object 800 in contact with the nozzle according to the collected data. According to the identification result of the object 800 in contact with the nozzle, the controller adjusts the duty cycle of the square-wave voltage to D and the period to T, and in addition, starts the booster motor so that its speed is N. After the adjustment, the current state (i.e., D, T, N) is maintained unchanged until the next sampling, and then the square-wave voltage and the booster motor are adjusted according to the result of the next sampling.

[0060] For example, when it is recognized that the object in contact with the nozzle is a blood thrombus mixture, the controller will adjust the duty cycle of the square-wave voltage to D1 and the working cycle to T1, and at the same time start the booster motor with a speed of N1 to start more efficient thrombus aspiration. Among them, D1 is greater than D0, and T1 < T0. When it is recognized that the object 800 in contact with the nozzle is a complete thrombus, the controller will further adjust the duty cycle of the square-wave voltage to D2, the working cycle to T2, and the speed of the booster motor to N2 to quickly remove the thrombus. Among them, D2 > D1, T2 < T1, and N2 > N1. In this embodiment, the working state of the negative pressure control valve is adjusted by identifying the type of the object in contact with the nozzle. When the proportion of blood in the object in contact with the nozzle is large, the opening time of the negative pressure control valve should be shortened at this time to reduce the suction volume of healthy blood, and at the same time, the speed of the booster motor should be reduced to reduce the high-pressure liquid sprayed into the blood vessel. When the proportion of thrombus in the object in contact with the nozzle is large, the opening time of the negative pressure control valve should be increased at this time to aspirate more thrombus per unit time, and the speed of the booster motor should be increased to use the high-speed jet to break the thrombus sucked into the suction catheter 300 and reduce the blockage probability. For the period T of the square-wave voltage, the smaller the period T, the more precise the control of the negative pressure control valve. When the proportion of thrombus in the object in contact with the nozzle is large, the period T can be reduced to more precisely control the thrombus aspiration process. Of course, in other embodiments, the period T can also remain unchanged and be a constant value.

[0061] The embodiments described above are merely examples of several implementations of the present invention, and while the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the invention patent. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of the present invention, and these all fall within the scope of protection of the present invention. The scope of protection of this patent should be determined by the appended claims.

Claims

1. A thrombus aspiration system, characterized in that, include: A suction catheter having a suction cavity and an opening at its distal end; An electrode assembly is disposed at the tube opening, and the electrode assembly contacts the tube opening contact material and measures its impedance value. A controller that acquires the impedance value and determines the type of the contact material at the nozzle based on the impedance value.

2. The thrombus aspiration system according to claim 1, characterized in that, The electrode assembly includes a first power electrode, a first measuring electrode, a second power electrode, and a second measuring electrode arranged in a circular pattern. The first power electrode and the second power electrode are arranged radially opposite to each other, and the first measuring electrode and the second measuring electrode are arranged radially opposite to each other. Adjacent electrodes are connected by an insulator.

3. The thrombus aspiration system according to claim 1, characterized in that, The electrode assembly measures at least three impedance values ​​of the tube contacts under AC power at different frequencies, and the controller obtains the intracellular fluid resistance R1, cell membrane capacitance C, and plasma resistance R0 based on the at least three impedance values.

4. The thrombosis control system according to claim 4, characterized in that, The controller determines the biometric index f based on the intracellular fluid resistance R1, cell membrane capacitance C, and plasma resistance R0, where f = w1R0 + w2R1 + w3C, and w1, w2, and w3 are weighting coefficients. The controller determines the type of material in contact with the tube opening based on the biometric index f.

5. The thrombosis control system according to claim 4, characterized in that, The controller determines the value range to which the biometric index f belongs based on the value range to which the biometric index f belongs, and the controller determines the type of material to which the nozzle contacts based on the value range to which the biometric index f belongs.

6. The thrombosis control system according to claim 5, characterized in that, It also includes a negative pressure control valve, the proximal end of which is connected to a vacuum source and the distal end of which is connected to the suction chamber; the controller applies a square wave voltage to drive the negative pressure control valve, and the controller adjusts the duty cycle of the square wave voltage according to the type of object contacted by the nozzle.

7. The thrombosis control system according to claim 6, characterized in that, The controller adjusts the period of the square wave voltage according to the type of contact object at the nozzle.

8. The thrombosis control system according to claim 5, characterized in that, The suction conduit also has a high-pressure chamber, which is isolated from the suction chamber; it also includes a booster motor and a high-pressure pump, the booster motor drives the high-pressure pump to move, and the high-pressure chamber is connected to the output end of the high-pressure pump; the controller adjusts the speed of the booster motor according to the type of object contacted by the conduit.

9. A control method for a thrombus aspiration system, characterized in that, include: Obtain at least three impedance values ​​of the contact material at the nozzle of the suction catheter at different frequencies; Based on the at least three impedance values, determine the intracellular fluid resistance R1, the cell membrane capacitance C, and the plasma resistance R0; Based on the intracellular fluid resistance R1, cell membrane capacitance C, and plasma resistance R0, the biological characteristic index f is determined, f = w1R0 + w2R1 + w3C, where w1, w2, and w3 are weighting coefficients. The numerical range to which the biometric index f belongs is determined based on the index. The type of material in contact with the nozzle is determined based on the numerical range of the biometric index f.

10. The control method according to claim 9, characterized in that, The thrombus aspiration system includes a negative pressure control valve connected between a vacuum source and the aspiration catheter, and the duty cycle of the square wave voltage driving the negative pressure control valve is adjusted according to the type of object contacted by the catheter port.

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