CN113520353A

CN113520353A - Use method of catheter simulator

Info

Publication number: CN113520353A
Application number: CN202110811105.5A
Authority: CN
Inventors: 熊双涛; 郑欲晓
Original assignee: Insight Lifetech Co Ltd
Current assignee: Insight Lifetech Co Ltd
Priority date: 2018-12-31
Filing date: 2018-12-31
Publication date: 2021-10-22
Anticipated expiration: 2038-12-31
Also published as: CN113520354A; CN109567776A; CN109567776B; CN113520353B; CN113520354B

Abstract

The present disclosure relates to a method of using a catheter simulator for testing an FFR host system, the catheter simulator comprising a generation module, a processing module, an adjustment module, and a matching module having a first wheatstone half-bridge circuit, the FFR host system having a second wheatstone half-bridge circuit, the first Wheatstone half-bridge circuit is matched with the second Wheatstone half-bridge circuit to make the catheter simulator matched with the FFR host system in circuit, the generation module generates a blood pressure periodic signal, the processing module converts the blood pressure periodic signal into a blood pressure differential signal, the blood pressure differential signal is adjusted through the adjusting module to obtain a low-amplitude differential signal, the low-amplitude differential signal is output to be a matching differential signal matched with the FFR host system through the matching module, and the FFR host system receives the matching differential signal and generates a blood flow reserve fraction based on the matching differential signal. According to the present disclosure, the reliability of the test can be improved.

Description

Use method of catheter simulator

The application is filed as31/12/2018Application No. is201811650741.9The invention is named asFor Catheter simulator for testing FFR host systemDivisional application of the patent application.

Technical Field

The present disclosure relates to a method of using a catheter simulator.

Background

In many cardiovascular diseases such as coronary heart disease, stenosis of a blood vessel (caused by, for example, a plaque of the blood vessel) affects the normal supply of blood, and when the blood vessel is further narrowed or even blocked, it may cause a serious disease such as myocardial infarction. Percutaneous Coronary Intervention (PCI) is currently the more effective treatment.

In recent years, in order to accurately judge whether a patient really needs to perform an interventional therapy, the use of Fractional Flow Reserve (FFR) for evaluating the degree to which a stenotic lesion obstructs blood Flow through a blood vessel has been increasingly applied and popularized. FFR refers to the ratio of the maximum blood flow obtained from the myocardial region supplied by the blood vessel in the presence of a stenotic lesion to the maximum blood flow obtained from the same region under theoretically normal conditions, i.e. the ratio of the mean blood pressure (Pd) in the stenotic distal coronary artery to the mean blood pressure (Pa) in the coronary artery oral aorta in the state of maximal hyperemia of the myocardium. To calculate the FFR of a given stenosis (i.e., a site where stent placement is possible) within a vessel, blood pressure readings need to be measured and collected separately on the distal side of the stenosis (e.g., downstream of the stenosis, away from the aorta) and on the proximal side of the stenosis (e.g., upstream of the stenosis, near the aorta). Clinical studies have shown that the higher the stenosis, the lower the FFR, and that a FFR less than an assessment value (e.g., 0.8) may be a useful criterion upon which a physician may decide whether to administer an interventional procedure to such a patient. The validity of this criterion has also been confirmed by a number of large clinical studies (e.g., FAME clinical studies) in europe and america.

As a method of measuring the FFR of a patient, for example, there is a method using an FFR measurement system. The system mainly comprises three parts, namely a pressure measurement conduit, a pressure sensor and an FFR host system. The pressure measurement catheter is used for measuring a Pd value in a blood vessel, the pressure sensor is used for measuring a Pa value, the FFR host system is provided with a Pd interface and a Pa interface, the Pd value and the Pa value can be read, and the FFR is calculated after processing and analysis.

In order to make the measured FFR more accurate, we need to test the function of the FFR host system to verify its qualification. At present, the functional test of the FFR host system is mainly completed by applying a pressure measuring conduit to a hydraulic signal source outside the body. Specifically, a test platform including a hydraulic signal source is used for simulating a blood vessel and blood flow in the blood vessel in a patient, then a pressure value (corresponding to the Pd value) of the hydraulic signal source is measured by using a pressure measurement catheter, the measured Pd value is transmitted to an FFR host system, an existing pressure sensor simulator transmits the Pa value to the FFR host system, and the FFR host system calculates FFR (measured value) according to the simulated Pa value and the measured Pd value.

The function of the FFR host system is tested by comparing the measured value with the actual value set by the test platform. However, in the existing testing method, the requirement on the stability of the hydraulic signal source is very high, the hydraulic signal source is easily affected by external vibration to cause pressure fluctuation, so that the testing result is unreliable, and in addition, an actual pressure measuring guide pipe is required to be used in the testing process, so that the loss of the pressure measuring guide pipe is caused.

Disclosure of Invention

The present disclosure has been made in view of the above-mentioned state of the art, and an object thereof is to provide a catheter simulator capable of accurately and conveniently testing an FFR host system.

To this end, the present disclosure provides a catheter simulator for testing an FFR host system, comprising: a generation module which generates a blood pressure periodic signal based on the human blood pressure characteristic and the excitation voltage generated by the FFR host system; the processing module is used for processing the blood pressure periodic signal to generate a blood pressure differential signal; an adjusting module for adjusting the amplitude of the blood pressure differential signal to generate a low amplitude differential signal; and a matching module to output the low amplitude differential signal as a matched differential signal matched to the host system, wherein the FFR host system generates Fractional Flow Reserve (FFR) based on the matched differential signal.

In the catheter simulator for testing the FFR host system, the generation module generates a blood pressure periodic signal based on the blood pressure characteristic of a human body and the excitation voltage generated by the FFR host system, and generates a blood pressure differential signal after being processed by the processing module, so that the influence of external vibration on a hydraulic signal source can be effectively reduced, the reliability of the test is improved, the operation for generating the blood pressure periodic signal is simple, the difficulty in building a test platform is reduced, the catheter simulator is used for replacing a catheter, the loss of the catheter can be reduced, and the cost of the test is reduced.

In addition, in the catheter simulator for testing the FFR host system according to the present disclosure, optionally, the generating module includes a processing unit for generating a digital signal based on the blood pressure characteristics of the human body, and a converting unit for converting the digital signal into the blood pressure cycle signal. Therefore, the interference of the external environment to a signal source required by the test can be reduced, and the blood pressure periodic signal which effectively simulates the blood pressure characteristic of the human body is generated.

Additionally, in a catheter simulator for testing FFR host systems to which the present disclosure relates, optionally, the human blood pressure characteristic comprises a human blood pressure frequency. Thus, a blood pressure periodic signal having a frequency including the blood pressure of the human body can be effectively simulated.

In addition, in the catheter simulator for testing an FFR host system according to the present disclosure, optionally, the conversion unit has a digital-to-analog conversion subunit for converting the digital signal into an analog signal based on the excitation voltage, and an integration subunit for performing a filtering process on the analog signal to generate the blood pressure period signal. . Therefore, the excitation voltage from the FFR host system can be matched with the matched differential signal generated by the catheter simulator and the FFR host system more optimally, the precision of the blood pressure periodic signal can be effectively improved due to the stable excitation voltage, and the filtering processing of the integral subunit contributes to smoothing the whole blood pressure periodic signal.

In addition, in the catheter simulator for testing an FFR host system according to the present disclosure, optionally, the processing module is a differential conversion unit for converting the blood pressure periodic signal as a single-ended signal into the blood pressure differential signal. Therefore, noise brought to the signal by the external environment can be effectively reduced.

In addition, in the catheter simulator for testing the FFR host system according to the present disclosure, optionally, the adjustment module performs an attenuation process with a preset multiple on the blood pressure differential signal. Therefore, the signal amplitude of the blood pressure differential signal can be effectively reduced, and the requirement of the FFR host system on the signal amplitude can be met.

Additionally, in a catheter simulator for testing an FFR host system to which the present disclosure relates, optionally, the matching module has a first wheatstone half-bridge circuit, the FFR host system has a second wheatstone half-bridge circuit, the first wheatstone half-bridge circuit and the second wheatstone half-bridge circuit are matched to form a wheatstone full-bridge circuit. Therefore, the catheter simulator can be matched with a host system in the circuit through the Wheatstone full-bridge circuit.

In addition, in the conduit simulator for testing an FFR host system according to the present disclosure, optionally, the matching module further has a memory for storing calibration parameters of the conduit, the calibration parameters including a first functional relationship between a first resistance value of a constant-value resistive element of the conduit and a temperature of the conduit, and a second functional relationship between a second resistance value of a pressure-sensitive resistive element of the conduit and an ambient pressure to which the conduit is subjected. Under the condition, the host system can be calibrated based on the calibration parameters of the resistance of the conduit and the temperature of the conduit, so that the temperature factor of the conduit is fully considered in the test process, the test reliability is improved, and the test accuracy is further improved through the functional relation between the resistance value and the pressure.

Additionally, in a catheter simulator for testing FFR host systems to which the present disclosure relates, optionally, the first wheatstone half-bridge circuit has a variable resistance element. Thereby, the conduit simulator can better simulate the conduit by adjusting the resistance value of the variable resistance element of the first Wheatstone half-bridge circuit.

Further, in a catheter simulator for testing an FFR host system to which the present disclosure relates, optionally, the matching module adjusts a resistance value of the variable resistance element based on the calibration parameter, a resistance of the catheter, and a circuit impedance of the FFR host system to match the matched differential signal to the FFR host system. In this case, the matching differential signal generated by the conduit simulator can be further better matched to the host system.

According to the test platform, the influence that a hydraulic signal source is easily affected by external vibration can be effectively reduced, the test reliability is improved, the operation of generating blood pressure periodic signals is simple, the difficulty of building the test platform is reduced, the conduit simulator is used for replacing a pressure measurement conduit, the loss of the pressure measurement conduit can be reduced, and the test cost is reduced.

Drawings

Embodiments of the present disclosure will now be explained in further detail, by way of example only, with reference to the accompanying drawings, in which:

fig. 1 is a schematic diagram showing an application of a catheter simulator according to an embodiment of the present disclosure;

FIG. 2 is a block diagram illustrating a catheter simulator in accordance with an embodiment of the present disclosure;

FIG. 3 is a block diagram illustrating a generation module of a catheter simulator in accordance with an embodiment of the present disclosure;

fig. 4 is a block diagram illustrating a conversion unit of a generation module of a catheter simulator in accordance with an embodiment of the present disclosure;

FIG. 5 is a block diagram illustrating a matching module of a catheter simulator in accordance with embodiments of the present disclosure;

fig. 6 is a block diagram illustrating an FFR host system to which a catheter simulator according to an embodiment of the present disclosure is applied;

fig. 7 is a wheatstone full-bridge circuit diagram showing a configuration in which a first wheatstone half-bridge circuit of a matching module of a catheter simulator according to an embodiment of the present disclosure is matched with a second wheatstone half-bridge circuit of an applied FFR host system; and

fig. 8 is a flowchart illustrating operation of a catheter simulator according to an embodiment of the present disclosure.

Detailed Description

All references cited in this disclosure are incorporated by reference in their entirety as if fully set forth. Unless defined otherwise, technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this disclosure belongs.

General guidance for many of the terms used in this application is provided to those skilled in the art. Those of skill in the art will recognize many methods and materials similar or equivalent to those described herein that can be used in the practice of the present disclosure. Indeed, the disclosure is in no way limited to the methods and materials described.

Fig. 1 is a schematic diagram showing an application of a catheter simulator according to an embodiment of the present disclosure. Fig. 2 is a block diagram illustrating a catheter simulator according to an embodiment of the present disclosure.

A catheter simulator 1 for testing an FFR host system 2 (hereinafter sometimes also referred to as "host system 2") according to embodiments of the present disclosure may include a generation module 10, a processing module 20, an adjustment module 30, and a matching module 40. In the catheter simulator 1, the generation module 10 may generate a blood pressure cycle signal Vt based on the human blood pressure characteristics and the excitation voltage Vi generated by the FFR host system 2. In addition, the processing module 20 may be configured to process the blood pressure cycle signal Vt to generate the blood pressure difference signal Vd. The adjusting module 30 may be configured to adjust the signal amplitude of the blood pressure differential signal Vd to generate a low amplitude differential signal Vl. Additionally, the matching module 40 may be configured to output the low amplitude differential signal Vl as a matching differential signal Vm that matches the FFR host system 2, wherein the FFR host system 2 generates a Fractional Flow Reserve (FFR) based on the matching differential signal Vm.

In this embodiment, the blood pressure periodic signal Vt generated by the generation module 10 in the form of an electrical signal is relatively stable, so that the signal source of the test platform is effectively prevented from being affected by external vibration. In addition, the generation module 10 can simulate a human body blood pressure signal with a wider frequency range, the test accuracy is effectively improved, the operation of generating the blood pressure periodic signal Vt is simple, the difficulty of building a test platform is reduced, and the catheter simulator 1 is used for replacing a pressure measurement catheter, so that the test cost can be greatly reduced. In addition, since the catheter simulator 1 has the first wheatstone half-bridge circuit 41 and the FFR host system 2 has the second wheatstone half-bridge circuit 2a (see fig. 6 described later), the catheter simulator 1 and the FFR host system 2 can be more optimally matched.

The catheter simulator 1 according to the present embodiment is particularly suitable for simulating a Pd value obtained by a pressure measuring catheter in a measurement system.

Fig. 3 is a block diagram illustrating a generation module of a catheter simulator in accordance with an embodiment of the present disclosure. Fig. 4 is a block diagram illustrating a conversion unit of a generation module of a catheter simulator according to an embodiment of the present disclosure. Fig. 5 is a block diagram illustrating a matching module of a catheter simulator in accordance with an embodiment of the present disclosure. Fig. 6 is a block diagram illustrating an FFR host system to which a catheter simulator according to an embodiment of the present disclosure is applied.

In this embodiment, the generation module 10 may generate the blood pressure cycle signal Vt based on the blood pressure characteristics of the human body and the excitation voltage Vi generated by the FFR host system 2.

In the present embodiment, the term "human blood pressure characteristics" generally refers to frequency and amplitude fluctuations of a certain characteristic that are generated by blood pressure in a blood vessel according to the heartbeat when the human heart pumps blood. In some examples, the human blood pressure characteristics include primarily the frequency, amplitude, etc. of the fluctuations in human blood pressure. In the present embodiment, the "blood pressure cycle signal" Vt generally refers to a signal having a characteristic of human blood pressure and having a repetitive cyclic change. In some examples, the blood pressure periodic signal may be a sinusoidal signal.

In the present embodiment, the excitation voltage Vi generated by the FFR host system 2 generally refers to a voltage generated by the FFR host system 2 and transmitted to the catheter simulator 1. The use of the excitation voltage Vi generated by the FFR host system 2 is advantageous for better matching of the catheter simulator 1 and the FFR host system 2.

In addition, in the present embodiment, the generation module 10 may include a processing unit 11 and a conversion unit 12. In this embodiment, in the generating module 10, the processing unit 11 may be configured to generate a digital signal based on the blood pressure characteristics of the human body.

In the present embodiment, the "digital signal" generated by the processing unit 11 generally refers to a signal in which an independent variable is discrete and a dependent variable is also discrete. In computers, the magnitude of a digital signal is often represented by a binary number with a limit. In some examples, the digital signal may include a frequency characteristic of human blood pressure.

In some examples, the processing unit 11 may be a micro-processor (MCU), a Central Processing Unit (CPU), a field programmable array (FPGA) having a processor function, or the like.

In addition, the conversion unit 12 may be used to convert the digital signal into the blood pressure cycle signal Vt. This enables generation of a blood pressure cycle signal Vt having characteristics of human blood pressure. In some examples, the blood pressure cycle signal Vt may be a sinusoidal signal.

In addition, in the present embodiment, in some examples, the conversion unit 12 may have a digital-to-analog conversion subunit 121 for converting a digital signal into an analog signal based on the excitation voltage Vi, and an integration subunit 122 for performing a filtering process on the analog signal to generate the blood pressure cycle signal Vt. Thus, the excitation voltage Vi from the FFR host system 2 can match the signal generated by the catheter simulator 1 to the FFR host system 2 more favorably, and the stable excitation voltage Vi can effectively improve the accuracy of the blood pressure cycle signal Vt, and the filtering process by the integrating unit contributes to smoothing the whole blood pressure cycle signal Vt.

In this embodiment, the filtering process performed by the integrator unit 122 can filter the portion with significant difference in signal, so as to make the blood pressure cycle signal Vt smoother. In some examples, the integration subunit 122 may filter out high frequency signals in the blood pressure cycle signal Vt.

Additionally, in some examples, the integrating sub-unit 122 may include an integrating circuit capable of performing a filtering process.

In addition, in the present embodiment, the processing module 20 may be configured to convert the blood pressure cycle signal Vt, which is a single-ended signal, into the blood pressure differential signal Vd. Therefore, noise brought to the signal by the external environment can be effectively reduced.

In the present embodiment, the single-ended signal and the differential signal are generally referred to as signal transmission techniques. A single-ended signal generally means that a signal is composed of a reference end and a signal end, and the reference end is generally a ground end; the difference is generally to perform differential transformation on a single-end signal to output two signals, one of which is in phase with the original signal and the other of which is in phase opposite to the original signal, and the difference between the two signals is the differential signal. When the interference of the external environment occurs, because the two signals change simultaneously, the change of the difference between the two signals is usually small, that is, the change of the differential signal is usually small, so the differential signal usually has strong anti-interference capability.

In addition, in the present embodiment, the adjustment module 30 may perform attenuation processing with a preset multiple on the blood pressure difference signal Vd. Therefore, the signal amplitude can be reduced, so that the requirement of the FFR host system 2 on the signal amplitude can be met. In some examples, the preset multiple may be 100 to 1000 or a corresponding order of magnitude.

In the present embodiment, the adjustment module 30 performs an attenuation process on the blood pressure difference signal Vd, that is, performs an amplification process with a preset multiple on the blood pressure difference signal Vd. Specifically, because the amplitude of the signal transmitted by the actual pressure measurement catheter is usually small, the FFR host system usually needs to process the signal with a low amplitude level, while in the catheter simulator 1, the amplitude of the blood pressure periodic signal Vt generated by the generation module 10 is high, and in order to meet the requirement of the FFR host system 2 on the signal amplitude, the blood pressure differential signal Vd needs to be attenuated to obtain the low-amplitude differential signal Vl. In other words, the blood pressure difference signal Vd is amplified, and the amplitude of the amplified signal is smaller than the amplitude of the original signal. In some examples, the original signal amplitude may be 1000 times the amplified signal amplitude.

Fig. 7 is a wheatstone full-bridge circuit diagram showing a configuration in which a first wheatstone half-bridge circuit of a matching module of a catheter simulator according to an embodiment of the present disclosure is matched with a second wheatstone half-bridge circuit of an applied FFR host system.

In the present embodiment, the matching module 40 may have a first wheatstone half-bridge circuit 41, the FFR host system 2 generally has a second wheatstone half-bridge circuit 2a, and the first wheatstone half-bridge circuit 41 and the second wheatstone half-bridge circuit 2a are matched to form a wheatstone full-bridge circuit. This enables the catheter simulator 1 to be electrically matched to the FFR host system 2.

In the present disclosure, a wheatstone half-bridge circuit and a wheatstone full-bridge circuit are generally one type of circuit connection. The Wheatstone half-bridge circuit comprises 2 parallel lines and 2 resistors, and each parallel line comprises 1 resistor. The Wheatstone full bridge circuit comprises 2 parallel lines and 4 resistors, and each parallel line comprises two resistors. The wheatstone half-bridge circuit can be regarded as a half of the wheatstone full-bridge circuit.

In this embodiment, in some examples, the first wheatstone half-bridge circuit 41 may include two variable resistive elements Rx1, Rx2, by adjusting the resistance values of the variable resistive elements Rx1, Rx2, to enable simulation of the resistance of the internal circuit in the pressure measurement catheter.

In the wheatstone full bridge circuit shown in fig. 7, the resistor R1 and the resistor R2 form the second wheatstone half bridge circuit 2a, the resistors Rx1 and Rx2 form the first wheatstone half bridge circuit 41, and the second wheatstone half bridge circuit 2a and the first wheatstone half bridge circuit are connected to form the wheatstone full bridge circuit.

In some examples, the fixed-value resistive element in the pressure measurement conduit may be simulated using variable resistive element Rx1 and the piezoresistive element in the pressure measurement conduit may be simulated using variable resistive element Rx 2.

In some examples, variable resistance element Rx1 may also be used to simulate a pressure sensitive resistance element in a pressure measurement catheter and variable resistance element Rx2 may also be used to simulate a fixed value resistance element in a pressure measurement catheter.

In addition, in the present embodiment, the matching module 40 may further have a memory 42 for storing calibration parameters of the conduit, and the calibration parameters may include a first functional relationship between a first resistance value of a constant-value resistive element of the pressure measurement conduit and a temperature of the pressure measurement conduit, and a second functional relationship between a second resistance value of a pressure-sensitive resistive element of the pressure measurement conduit and an external pressure applied to the pressure measurement conduit. Therefore, the temperature factor can be conveniently and fully considered in the operation process of the host system, and the reliability of the test is improved.

In the present embodiment, the varistor element generally refers to a resistor element whose resistance value changes with a change in the magnitude of pressure. In some examples, the resistance value of the piezoresistive element may be positively or negatively correlated with pressure.

In this embodiment, the variable resistive element generally refers to a resistive element whose resistance value can be changed by manual adjustment. The duct simulator 1 can simulate a pressure measuring duct by simulating the circuit characteristics inside the pressure measuring duct, for example, by adjusting a variable resistance element so that the resistance value of the first wheatstone half-bridge circuit 41 is equal to the resistance value of the internal circuit of the pressure measuring duct.

In addition, in the present embodiment, the matching module 40 may adjust the resistance value of the variable resistance element based on the calibration parameter, the resistance of the pressure measurement conduit, and the circuit impedance of the FFR host system 2 so that the matching differential signal Vm matches the FFR host system 2. Therefore, the FFR host system 2 can conveniently process the signals generated by the catheter simulator 1 to generate the FFR, and the measured value and the set value are compared to test the qualification of the FFR host system 2.

In some examples, in the catheter simulator 1 in the present disclosure, the blood pressure cycle signal Vt may be a sinusoidal signal.

In some examples, the conduit simulator 1 to which the present disclosure relates, the frequency range of the digital signal may be 0 to 5 hertz (Hz). In some examples, the frequency of the digital signal may be selected to be 0 hertz, 1 hertz, 2 hertz, 3 hertz, 4 hertz, or 5 hertz.

In some examples, the catheter simulator 1 described in the present disclosure may be used to simulate a human blood pressure signal. In some examples, the catheter simulator 1 of the present disclosure may simulate digital signals of one or more particular frequencies.

In this embodiment, the processing unit 11 may have a microcomputer circuit therein, and may process the input power signal based on the frequency characteristic of the blood pressure of the human body to generate a digital signal, wherein the frequency and amplitude of the digital signal may be in accordance with the characteristic of the actual blood pressure signal of the human body.

In the catheter simulator 1 of the present disclosure, the conversion unit 12 of the generation module 10 may convert the digital signal into an analog signal as the blood pressure cycle signal Vt. In some examples, the blood pressure cycle signal Vt may be a sinusoidal signal.

In some examples, the processing module 20 of the catheter simulator 1 in the present disclosure may convert the single-ended signal as the blood pressure cycle signal Vt into a differential signal as the blood pressure differential signal Vd. Therefore, the interference on the signal transmission process can be effectively reduced, and the blood pressure differential signal Vd is more accurate and reliable.

In some examples, the adjustment module 30 in the catheter simulator 1 of the present disclosure may attenuate the blood pressure differential signal Vd.

In some examples, the adjusting module 30 of the catheter simulator 1 in the present disclosure may have an amplifying circuit, and may perform attenuation processing of a preset multiple on the input blood pressure differential signal Vd. Since the signal in the pressure measurement conduit is small, the signal of the common signal source needs to be attenuated by a preset multiple without losing great precision, so as to achieve a closer simulation effect.

In some examples, the matching module 40 may have a first wheatstone half-bridge circuit 41 and the FFR host system 2 may have a second wheatstone half-bridge circuit 2 a.

In this embodiment, the FFR host system 2 needs to calculate and process the matching differential signal Vm transmitted by the catheter simulator 1 to obtain the FFR. During operation, some fixed values need to be used, such as the resistance values of R1, R2 in the second wheatstone half-bridge circuit 2a in the FFR host system 2, the resistance values of Rx1, Rx2 in the first wheatstone half-bridge circuit 41 in the catheter simulator 1, the functional relationship between the resistance values of the piezoresistive elements of the internal circuit of the pressure measuring catheter and the pressure, and the functional relationship between the resistance values of the fixed-value resistive elements of the internal circuit of the pressure measuring catheter and the temperature of the catheter. In this way, the internal circuit of the pressure measurement catheter is simulated by using the first wheatstone half-bridge circuit 41 of the matching module 40, so that the second wheatstone half-bridge circuit 2a in the FFR host system 2 is matched with the first wheatstone half-bridge circuit 41 of the matching module 40 to form a wheatstone full-bridge circuit.

The method of using the catheter simulator 1 is described in detail below in conjunction with the flow chart shown in fig. 8.

In step S10, since the catheter simulator 1 is connected to the FFR host system 2, the excitation voltage Vi generated by the FFR host system can be transmitted to the catheter simulator 1.

In step S20, the processing unit 11 of the generation module 10 of the catheter simulator 1 generates a digital signal having frequency characteristics of human blood pressure. Then, the digital-to-analog conversion sub-unit 121 of the conversion unit 12 can convert the digital signal into an analog signal based on the above-described excitation voltage Vi. Then, the integrating subunit 122 performs filtering processing on the analog signal to obtain a smoothed blood pressure cycle signal Vt.

In step S30, the processing module 20 of the catheter simulator 1 has a single-ended to differential function, and can convert the single-ended signal as the blood pressure cycle signal Vt into the blood pressure differential signal Vd. Therefore, noise brought to the signal by the external environment can be effectively reduced.

In step S40, the adjustment module 30 of the catheter simulator 1 has a circuit-sense amplification function, and can perform an attenuation process on the blood pressure differential signal Vd with a higher signal amplitude to obtain a low-amplitude differential signal Vl with a lower signal amplitude. This may achieve the signal amplitude requirements of the FFR host system 2, resulting in a better match of the catheter simulator 1 to the FFR host system 2.

In step S50, the matching module 40 of the catheter simulator 1 has a first wheatstone half-bridge circuit 41 and a memory 42, the first wheatstone half-bridge circuit 41 being matchable with the second wheatstone half-bridge circuit 2a of the FFR host system to form a wheatstone full-bridge circuit as shown in fig. 7, by which the low-amplitude differential signal Vl is output as the matching differential signal Va.

In step S60, the FFR host system 2 receives the matching differential signal Va from the catheter simulator 1, analyzes and processes the matching differential signal Va, and calculates FFR. The calculated measurements are then compared to the set point for the test platform. By comparing the difference between the measured value and the set value, the function of the FFR host system 2 is evaluated, and the test work of the FFR host system is completed.

While the present disclosure has been described in detail in connection with the drawings and examples, it should be understood that the above description is not intended to limit the disclosure in any way. Those skilled in the art can make modifications and variations to the present disclosure as needed without departing from the true spirit and scope of the disclosure, which fall within the scope of the disclosure.

Claims

1. A method for using a conduit simulator, which comprises the steps of,

the conduit simulator for simulating circuit characteristics inside a pressure measurement conduit to test an FFR host system, the conduit simulator including a generation module, a processing module, an adjustment module, and a matching module having a first Wheatstone half-bridge circuit, the FFR host system having a second Wheatstone half-bridge circuit,

the using method comprises the following steps:

through first wheatstone half-bridge circuit with second wheatstone half-bridge circuit matches in order to constitute wheatstone full-bridge circuit, so that the pipe simulator with FFR host computer system matches on the circuit, the pipe simulator receives the produced excitation voltage of FFR host computer system, through the generation module based on human blood pressure characteristic with the excitation voltage is with generating blood pressure cycle signal, through processing module will blood pressure cycle signal converts blood pressure differential signal into blood pressure differential signal, through the adjustment module adjusts the blood pressure differential signal is in order to obtain low amplitude differential signal, through the matching module will low amplitude differential signal output be with the matching differential signal that FFR host computer system matches, FFR host computer system receives the matching differential signal and based on matching differential signal generation blood flow reserve fraction.

2. Use according to claim 1, characterized in that:

the matching module also has a memory for storing calibration parameters of the pressure measurement catheter, the calibration parameters including a first functional relationship between a first resistance value of a fixed-value resistive element of the pressure measurement catheter and a temperature of the pressure measurement catheter, and a second functional relationship between a second resistance value of a pressure-sensitive resistive element of the pressure measurement catheter and an ambient pressure to which the pressure measurement catheter is subjected.

3. Use according to claim 2, characterized in that:

the matching module adjusts a resistance value of the variable resistance element based on the calibration parameter, a resistance of the pressure measurement conduit, and a circuit impedance of the FFR host system to match the matched differential signal to the FFR host system.

4. Use according to claim 1, characterized in that:

the generation module comprises a processing unit for generating a digital signal based on the blood pressure characteristic of the human body and a conversion unit for converting the digital signal into the blood pressure periodic signal.

5. Use according to claim 4, characterized in that:

the frequency range of the digital signal is 0 to 5 hertz.

6. Use according to claim 4, characterized in that:

the human blood pressure characteristics include frequency and amplitude of blood pressure.

7. Use according to claim 4, characterized in that:

the conversion unit is provided with a digital-to-analog conversion subunit and an integration subunit, wherein the digital-to-analog conversion subunit is used for converting the digital signals into analog signals based on the excitation voltage, and the integration subunit is used for filtering the analog signals to generate the blood pressure periodic signals.

8. Use according to claim 1, characterized in that:

the blood pressure periodic signal is a sinusoidal signal.

9. Use according to claim 1, characterized in that:

the adjustment module performs attenuation processing with a preset multiple on the blood pressure differential signal, wherein the preset multiple is 100-1000.

10. Use according to claim 1, characterized in that:

testing the qualification of the FFR host system by comparing the measured fractional flow reserve with a set point of the catheter simulator.